UNIVERSITY OF APPLIED SCIENCESDepartment of Conservation

CHEMICAL SUBSTANCES IN MUSEUM COLLECTIONS: THE DECISION-MAKING

PROCESS IN THE CONSERVATION OF CHEMICAL SUBSTANCES AT THE POLICE

MUSEUM IN TAMPERE

Elzbieta DjupsjöbackaTextile Conservation

Master’s ThesisMay 2008

ABSTRACTUNIVERSITY OF APPLIED SCIENCES

Degree Programme: ConservationMajor: Textile ConservationMaster’s Thesis: Chemical substances in museum collections: The decision-

making process in the conservation of chemical substances at the Police Museum in Tampere.

Author: Elzbieta DjupsjöbackaYear: 2008Pages: 107 +17

The conservation of chemical substances from the collection of the Police Museum in Tampere inspired the studies presented in this thesis. The studies focused on three central issues in the conservation of chemical substances as part of a museum collection: the ethical and practical decisions regarding the preservation of difficult objects, the analysis and identification of said substances, and finally their practical conservation. The thesis is hence divided into three parts according to these issues, answering the questions “Why?”, “What?”, and “How?”.

The first part, entitled “Why?” discusses the need for preserving chemical substances even when they can prove hazardous to either staff or the rest of museum collection. The necessity of preserving the integrity of the object by saving not only the container, but also the chemical is discussed.

The second part “What?” takes a look at the various chemicals that may be encountered as part of museum collections. Identification of these chemicals is a key to correct decision-making. Some methods of identification and analysis are described in this section. As a practical example, the identification process of the chemicals at the Police Museum is described in detail.

The third part of the thesis presents general guidelines for how the preservation of chemicals should be undertaken and what aspects of active and preventive conservation should be considered, in particular when deciding on a storage or disposal plan for the substances. It provides some common standards that should be maintained when conserving chemical substances. In addition, this section contains examples of museums tasked with preserving chemical substances and brief descriptions of their solutions to the unique problems of this endeavour.

Keywords: chemical substances, identification of chemicals, museum collection of chemicals, hazardous chemicals in museum, disposal of chemical substances

MUOTOILUINSTITUUTTI TIIVISTELMÄ

Koulutusohjelma: KonservointiSuuntautumisvaihtoehto: Ylempi ammattikorkeakoulututkinto, Tekstiilikonservointi Opinnäytetyön nimi: Kemialliset aineet museokokoelmissa: Kemiallisten aineiden

konservointiin liittyvä päätöksentekoprosessi Tampereen Poliisimuseossa.

Tekijä: Elzbieta DjupsjöbackaVuosi: 2008Sivuja: 107 + 17

Tampereen Poliisimuseon kokoelmien kemiallisten aineiden konservointiin liittyvien ratkai-sujen tekeminen johti asian tutkimiseen laajemmasta näkökulmasta ja toimii pohjana tälle tutkielmalle. Kemiallisten aineiden konservointia osana museokokoelmia lähestytään kolmesta näkökulmasta: hankalien aineiden säilyttämiseen liittyvät eettiset ja käytännölliset ongelmat, aineiden analysointi ja tunnistaminen sekä niiden konservointi käytännössä. Tutkielma on sen perusteella jaettu kolmeen osaan pyrkien vastaamaan kysymyksiin ”Miksi?”, ”Mitä?” ja ”Miten?”.

Ensimmäisessä osassa, ”Miksi?”, keskustellaan kemiallisten aineiden säilyttämisen syistä, vaikka aineet voivatkin olla vaarallisia museon henkilökunnalle tai museon muille esineille. Luvussa käsitellään myös esineiden säilyttämistä kokonaisuuksina, ei pelkästään astian vaan myös sisällön tallettamisen merkitystä.

Tutkielman toinen osa, ”Mitä?”, käsittelee erilaisia kemiallisia aineita, joita museoiden ko-koelmissa voidaan kohdata. Näiden aineiden tunnistaminen on välttämätöntä oikeiden konservointipäätösten tekemiseksi. Luvussa esitellään joitakin analysointimenetelmiä, joita museoissa voidaan käyttää aineiden tunnistamisessa. Käytännön esimerkkinä esitellään Tampereen Poliisimuseon kemiallisten aineiden tunnistusprosessi.

Kolmannessa osassa, ”Miten?”, esitellään yleiset ohjeet kemiallisten aineiden säilyttämi-seen ja mitä aktiivisia ja säilyttäviä konservointimenetelmiä voidaan käyttää. Luvussa käsitellään myös aineiden varastoimiseen ja hävittämiseen liittyvää päätöksentekoa. Tutkielmaa varten kerättiin kyselytutkimuksella tietoa kemiallisten aineiden säilyttämisestä ja konservoinnista useissa museoissa maailmalla ja saatuja vastauksia käytetään esimerkkeinä tässä luvussa.

Avainsanoja: kemialliset aineet, kemialliset aineiden tunnistaminen, kemialliset aineet mu-seokokoelmissa, vaaralliset kemikaalit museossa, kemiallisten aineiden hävittäminen.

Table of contents

1. Why should we consider chemical substances worthy of historical preservation?......................................................................................................................1 1.1. Introduction............................................................................................................1

1.2. Museum object as a cult object..............................................................................21.3. Can chemicals and other difficult substances be classified as historical objects?. 3

1.3.1. Chemical substances as archaeological objects.............................................41.3.2. Chemical substances as antiquities................................................................51.3.3. Chemical substances as historic works..........................................................51.3.4. Chemical substances as heritage and cultural heritage..................................61.3.5. Chemical substances as conservation objects...............................................6

1.4. Chemical substances as an aspect of professional ethics.....................................82. What kinds of chemical substances are encountered as historical objects?.....10

2.1. Classification of chemical substances..................................................................112.1.1. Organic and inorganic substances................................................................112.1.2. Solids and liquids..........................................................................................122.1.3. Acids, bases and neutral substances............................................................13

2.1.3.1 Acids......................................................................................................132.1.3.2. Bases.....................................................................................................14

2.1.4. Toxic, dangerous and non-hazardous substances.......................................142.1.4.1. Hazardous substances..........................................................................142.1.4.2. Toxic substances...................................................................................152.1.4.3. Non-hazardous substances...................................................................17

2.2. Ageing process....................................................................................................172.3. Changes in the physical properties of chemical substances................................20

2.3.1. Changes in the state of matter......................................................................202.3.2. Hygroscopic properties and reactions with water..........................................232.3.3. Sedimentation and separation of chemical substances................................24

2.4. Changes in chemical properties...........................................................................252.4.1. Oxidation reaction.........................................................................................252.4.2. Changes in colour.........................................................................................262.4.3. Changes in odour..........................................................................................272.4.4. Precipitation.......................................................................................................282.4.5. Predicting chemical changes.............................................................................28

2.5. Effects of mould growth on chemicals in museum collections.............................292.6. Researching physical and chemical properties....................................................31

2.6.1. Sampling.......................................................................................................332.6.2. FTIR spectroscopy........................................................................................352.6.3. NIR - Near Infrared Spectroscopy.................................................................362.6.4. X-Ray Fluorescence Spectroscopy...............................................................362.6.5. X-ray Absorption Near Edge Structure (XANES)..........................................372.6.6. Raman spectroscopy....................................................................................372.6.7. Laser methods..............................................................................................382.6.8. Chromatography methods............................................................................38

2.7. Molecular Diversity Preservation International.....................................................392.8. Documentation of chemical substances in a museum.........................................39

3. Chemicals in the Police Museum collection in Tampere, Finland........................403.1. Where do they come from?.....................................................................................403.2. Present condition and storage of chemicals at the Police Museum in Tampere.....423.3. Types of chemicals in the collection of the Police Museum in Tampere and their characteristic...................................................................................................................453.4. Identification of chemicals from the collection of the Police Museum in Tampere

463.4.1. Description of conservation objects..............................................................463.4.2. FTIR spectroscopy........................................................................................553.4.3. pH measurement..........................................................................................703.4.4. X-Ray Fluorescence Spectroscopy...............................................................713.4.5. Smell.............................................................................................................733.4.6. Interpretation of research results..................................................................74

3.5. Active and preventive conservation of chemicals from the Police Museum in Tampere.........................................................................................................................743.6. Literature research of chemical and physical behaviours of chemicals the from Police Museum...............................................................................................................753.7. Decision-making...................................................................................................76

3.7.1. Disposal........................................................................................................783.7.2. Storage.........................................................................................................78

4. How to preserve chemicals in museum collections..............................................804.1. Preventive conservation of chemical substances in a museum...........................804.2. Standards for collecting and preserving chemicals..............................................81

4.2.1. Legal possession of chemicals.....................................................................814.2.2. Safety of the museum...................................................................................82

4.2.2.1. Health and Safety Policy concerning collection of chemicals.....................834.2.3. Disposal of chemical substances......................................................................84

4.3. Advice on the preservation of chemicals..............................................................854.3.1. Active conservation of chemicals..................................................................854.3.2. Preventive conservation of chemicals...........................................................86

4.3.2.1. Screw-top containers.............................................................................874.3.2.2. Ground glass jars...................................................................................884.3.2.3 Bail-top containers.................................................................................894.3.2.4. Metal lids................................................................................................894.3.2.5. Bakelite resin lids...................................................................................894.3.2.6. Double-container system.......................................................................90

4.4. How chemicals are preserved in museums – a survey........................................915. Conclusions...............................................................................................................98References......................................................................................................................100Table of Figures..............................................................................................................105Table of Photos...............................................................................................................106Table of Tables...............................................................................................................107Appendix 1. European hazard symbols.........................................................................A1-1Appendix 2. Common hazard symbols..........................................................................A2-1Appendix 3. IR spectra of chemicals from the collection of the Police Museum in Tampere and their analysis............................................................................................................A3-1Appendix 4. Characteristic IR Absorption .....................................................................A4-1

Acknowledgments:

The author of this thesis would like to thank Tiina Tuulosvaara-Kaleva, the curator of the

Police Museum in Tampere, for her friendly attitude and for allowing me to complete my

studies on the collection of chemicals in their museum.

Many thanks to my professional colleagues who answered my inquiries and shared their

experience concerning collections of chemicals: Jos Breukers, conservator from the

Nederlands Politiemuseum; Anna Ridley, assistant curator of the Justice & Police Museum

in Sydney; Anna Chan, assistant curator of the Hong Kong Science Museum; Henna

Sinisalo, curator of the Helsinki university Museum Arppeanum; Lee Ann Obos ,

Pharmaceutics Laboratory Instructor, Throop Pharmacy Museum Curator, Albany College

of Pharmacy; Briony Hudson, Keeper of the Museum Collections, Royal Pharmaceutical

Society of Great Britain; Elisabeth Huwer, Director of Deutsches Apotheken-Museum.

Finally I would like to thank Ulla Knuutinen, Principal Lecturer at EVTEK University of

Applied Science for her support, advice and for completing the demanding task of reading

and correcting my thesis.

1. Why should we consider chemical substances worthy of historical preservation?

1.1. Introduction

Museums’ collections worldwide may contain very different objects and substances

that all are a part of our heritage. Museums may have many problems with their

collections, and not only the usual ones like financial and logistical but also ethical

and professional that concern artefacts that are unusual, need special storage, or are

dangerous to other objects in the collections or to people.

The Museum of Hemingway has a collection of particularly unique objects. The

Museum of Hemingway is situated in the writer’s home in Key West (Florida, USA). It

has a problem with six-toed cats that are descended from a cat owned by

Hemingway. They are interesting as animals and have become an integral part of the

museum, but can they be considered a cultural heritage and preserved? The

presence of live museum objects requires a special licence from the U.S. Department

of Agriculture. (National Geographic 2007, p.5)

In this part of my thesis I will discuss the ethical problems that concern chemical

substances in museum collections. Chemical substances in museum collections may

not present the same dilemmas as six-toed cats, but they may also cause many

problems relating to their preservation, storage, and ethical considerations.

Most pharmaceutical museums include chemical substances and medicines in their

collecting programmes. There the chemicals were collected in order to study and

preserve the history of medicine. In other museums chemicals might only be a part of

the collection like cosmetics, laboratory reagents, dental and veterinary preparations,

dyes, germicides and pesticides. Sometimes these materials are parts of other

objects that are collected by the museum. Chemical substances may pose a health

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hazard to people, or cause a risk to the rest of the collection. They also tend to be a

focus for irrational concerns of the museum staff.

Chemicals and other “strange” or unknown substances in museums can prove to be a

big challenge for a conservator. There are many difficulties and problems with their

conservation, preservation and storage. The difficulties and problems are not only

connected to physical and chemical matters but also ethical and moral issues. These

issues should be discussed and understood by conservators. They should be

acknowledged and used in their decision-making process.

“One should make sure at the very outset that there is a truly philosophic basic so

that conservators shall not only be good practitioners, but scholars as well, knowing

not only what they do, but why they do it.” (Stout 1945, p 37).

There are many definitions to describe conservation objects, but how should

chemicals and substances like food, cosmetics, or medicines be categorized? What

discipline of specialist conservators should take care of them? Do they fit the

description of artefacts that belong to our heritage? Should they be preserved, and if

so, why should they be preserved?

“We really have only three alternatives in dealing with an existing historic resource:

we can keep it, we can change it, or we can destroy it. “ (McGilvray 1988, pp. 3-17).

In this section I will try to answer the above-mentioned questions drawing on theories

and concepts present in contemporary conservation and discuss which of the

alternatives McGilvray describes should be chosen when dealing with chemical

substances in museums.

1.2. Museum object as a cult object

For most museum visitors the most important part of the experience is to see the real

historical object. In our age of communication and worldwide access to the Internet,

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where images of museum objects can be viewed, people visit museums to see them

in reality.

Why is it so important for us to see the original object enclosed in a museum cabinet?

Why do copies placed in museums tend to be disappointing to visitors even if they are

equally effective at presenting the historical information?

Outi Peisa, the curator of Helsinki City Museum speaks about an “object’s energy” –

the information and feelings that the museum’s object awakens in a viewer. This

“energy”, however immaterial, tends to provoke the thoughts and emotions that draw

us to museums, to see the real object rather than replicas or images.

Tusquet writes that in many cases a copy may offer a more complete experience than

the authentic object, which may be significantly damaged, but most people still prefer

to view the original object rather than the copy, regardless of its quality. (Vinas 2005,

pp 31-41).

The authentic object with its aura, energy or feeling of nostalgia provides more

excitement than replicas. That feeling and the need for authenticity should be taken

into consideration when making decisions about the preservation of chemicals or

other “strange” objects.

1.3. Can chemicals and other difficult substances be classified as historical objects?

Many terms are used to describe objects that are valued as historical and need to be

preserved. They can be named antiquities, cultural property, historic objects,

archaeological objects, and heritage. (Vinas S.M., 2005).

The definitions of these terms are various and confusing. What objects should we

preserve? What criteria should they fulfil? Into what category do chemical substances

fall? In his book Vinas presents several definitions commonly used to describe

conservation objects. Which of the definitions would best fit objects like chemicals

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and perishables? The correct definition may be difficult to find when there are

problems even describing the category for chemical substances.

Usually when speaking about chemicals we visualize chemicals used in a laboratory,

stored in well-labelled bottles or boxes and relatively new. Their chemical content is

usually the same as the chemicals used in modern laboratories. Do they possess

historical value? Is their preservation necessary?

Most conservators would probably decide to dispose of chemicals because of their

potential danger to the rest of the collection, and preserve only their packaging as of

historical value. Some chemicals however, like for example pure natron salt (sodium

carbonate (Na2CO3.10H20)), a well known mineral found at an archaeological site and

that was used in ancient Egypt for mummification, can be considered as

archaeological objects and preserved in museums.

The problem is complicated by the fact that chemicals age and their content may

change. Are they then a source of reliable historical information?

Below, chemicals and other “strange” substances are discussed according to

categorization of museum objects proposed by Vinas. (Vinas 2005, pp 31-41).

1.3.1. Chemical substances as archaeological objects

During archaeological excavation some chemicals, medicines, foodstuffs or traces of

them can be found. The substances that are found in archaeological excavations can

be called archaeological objects. According to Johnson, archaeological objects are

not only the objects and samples recovered during excavation but also records

produced by the archaeologist at work. (Johnson 1993).

Usually there only minute amounts of chemicals, sometimes just traces which cannot

be preserved for museums as objects but which can only be tested for the historical

information that they contain.

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What about objects from not so far in the past? They may also become

archaeological objects some day and be a source of historical information. Vinas

gives an example of a contemporary bottle of beer that can probably give future

historians more information about our civilization than some contemporary pieces of

art. Many conservators would be tempted to dispose of the beer and preserve only

the bottle. (Vinas 2005, p.34)

1.3.2. Chemical substances as antiquities

Antiquities are considered objects that have become obsolete. This is mostly true and

can be an adequate name to describe chemical substances in museums. The word

antique and antiquity, however, is more connected to objects that also have some

artistic value, and not many antiquarians would consider a bottle of aniline from 1952

(artefact from the Police Museum in Tampere) used by the Traffic and Road Police for

testing the purity of Diesel oil an antique. On the other hand, some might describe a

bottle of wine from that year as an antique object.

1.3.3. Chemical substances as historic works

Historic works are objects that are useful to historians. They provide historical

knowledge or evidence. Chemicals and other “strange” substances may fit this

definition of a historical object very well, as objects that are worthy of preserving

because they contain historical information.

This definition of historic work is very broad and on its borders can be placed a

medicine case containing bottles of mixtures and herbs from the Middle Ages, but

also a bottle of Coca-Cola from the 1950s whose value is greater for collectors than

for historians.

A museum object has value only when it can provide historical information. According

to this, removing part of the object, like for example disposing of a chemical and

preserving only its package, decreases its historical value. Disposing of the chemical

6

removes some of the information and integrity of the object. A decision about

disposing of the chemical should be made cautiously and only if the chemical is

hazardous to store.

1.3.4. Chemical substances as heritage and cultural heritage

Cultural heritage ("national heritage" or just "heritage") is the legacy of physical

artefacts and intangible attributes of a group or society that are inherited from past

generations, maintained in the present, and bestowed for the benefit of future

generations. Often, what is considered cultural heritage by one generation may be

rejected by the next, to be revived again by a succeeding one.

We can place chemical substances within this definition. If anything that is transmitted

from the past belongs to our heritage then even chemicals that are relatively new and

do not have historically valuable information can be considered objects of cultural

heritage.

1.3.5. Chemical substances as conservation objects

The definition of a conservation object is not precise. The decision about conserving

and preserving one object and not conserving another is always made by museum

professionals on the basis of their knowledge and intuition. All of the above definitions

of museum objects can be used, but they do not fully describe a conservation object.

This fact may be directly linked to the difficulties conservators face when deciding

whether to conserve an object or not. (Leigh 1994, pp. 269 - 286).

If there is no definition regarding what should be preserved and conserved, then the

responsibility will have to be shouldered by museum professionals and conservators.

Bonsanti says that conservation is made up of technical, methodological, scientific,

and professional factors, as well as an attitude describing the conservators personal

and emotional relationship to the object they work on. (Bonsanti 1997, pp 109 - 112).

7

This attitude or intuition is difficult to trust, yet essential when deciding upon

conservation procedures.

From the middle of the 20th century, conservation can be considered scientific

conservation because of the use of hard science in the conservation process.

Conservators base their work on science, yet there will always remain aspects of their

work which require them to be comfortable with the intuition Bonsanti describes.

Responsible for making such difficult decisions about our heritage, conservators long

for a scientific explanation. What do conservators do when there are no answers or

scientific basis for decision-making? Is it experience, intuition or moral rules that help

them make the decision as to what should be preserved?

How should conservators deal with objects like chemicals that are difficult or maybe

even impossible to conserve, which may be dangerous to the rest of the collection, or

whose aging process is unknown to them. Artefacts may, however, contain historical

information that may be an important part of our heritage. Can conservators decide to

dispose of the chemicals and save only their packaging? Can they destroy the

integrity of an object only because part of it may need special storage and

maintenance? Can museum visitors be deprived of seeing this “real thing” for which

they came to the museum?

And one more question: what kind of a conservator is best suited for the conservation

of chemicals? Conservation professionals are divided into specialized fields according

to the material of the museum object: paper, textile, wood, stone, ceramic, metal, etc.

Only art conservation has its own specialized fields that are not always connected to

the material of which an object is made.

In addition to the usual materials listed above, other strange and unusual materials

can be found in museum collections, particularly in natural history, ethnographic, or

medical museums. Chemical substances can also be found in other museums as a

part of their collection. For example in police museums where the majority of the

8

collection is uniforms and weapons, crime scene investigation related chemicals can

be found as well.

The conservation and preservation of such objects requires specialized knowledge.

For most of the chemicals in museum collections we can speak only about research

and preventive conservation. Active conservation is probably limited to cleaning and

conserving the chemical’s container. The eventual disposing of a part of the object

also belongs to the conservation of chemicals.

1.4. Chemical substances as an aspect of professional ethics

Many international bodies describe the code of ethics for the practice of conservation

of cultural materials. They underline some important aspects of conservation that

must be taken into consideration.

1 Conservation practice must be governed by an informed respect for cultural

property, and its unique character.

2 In the conservation of cultural material, all actions must be governed by an

unswerving respect for the physical, historic, aesthetic and cultural integrity of the

object. (AICCM 1999, p. 15).

The conservation professional’s respect for the integrity of the cultural property is

heavily stressed in these codes. When conserving a cultural property, the

conservator should respect the integrity of the object by endeavouring to preserve its

material composition and culturally significant qualities through minimal intervention.

The original intention, usage, history and evidence of the cultural property must be

respected. This respect for the integrity of the cultural property shall be based upon

the study of the cultural property. (CAC 2000, p.5).

According to the ICOM code of ethics, an intervention on an historic or artistic object

must follow the sequence common to all scientific methodology: investigation of

source, analysis, interpretation and synthesis. Only then can the completed treatment

9

preserve the physical integrity of the object, and make its significance accessible.

(ICOM 1984).

The changing role of museums initiated substantial changes in conservators’ work.

Conservators working for museums often consider conservation objects as their

clients, causing new museum directives to occasionally challenge the conservator’s

code of ethics. The changing role of the museums presented conservators with a new

way of looking at the objects and asking themselves: what is actually being preserved

when only the physical object is being conserved? The object should not be

perceived only as a physical being but as a whole concept. Also for this reason the

integrity of the object is very important. (Clavir 1996, pp.99 -107 )

Chemical substances belong to our heritage and are part of our cultural property.

Therefore they should be preserved and conserved according to a professional code

of ethics. Conservators play an important role in supporting the value of authenticity

and objects as historical evidence and this role also extends to difficult objects like

chemical substances. Chemical substances in a museum collection may cause many

problems, but by preserving the integrity of the object we guarantee that important

information is not destroyed.

Scientific methodology in the field of conservation has been used for many years

already. Scientific reasoning influences conservation and other work at museums.

The code of professional ethics may, however, conflict with science. There is a

special relationship between ethical beliefs and a scientific approach. A scientific

assertion can be tested using methodology, whereas ethical beliefs cannot be tested.

They are concerned with understanding how people view the nature of “reality” and

the underlying principles of value statements. (Clavir, 2002)

This divergence between professional ethics and pragmatic consideration can be

observed when approaching the problem of preserving chemical substances. Some

of them may be hazardous to health or pose a danger to the rest of the collection and

their possible preservation may be very costly and complicated. Their disposal seems

to be the easier way of solving the problem. The conservation code of ethics,

10

however, proposes that removing a part of an object, for example chemicals from

their container and disposing of them, is not ethical and does not respect the object’s

integrity. What values are more important? When deciding about preserving

hazardous substances many aspects must be weighed: on the one hand possible

dangers to people, on the other historical and cultural value. If the chemical in

question is a common, well known substance that is produced in large amounts

nowadays like, for example, acetic acid, the decision about disposal is easier to

make. It is more difficult to make a decision about an ethnographic object that

contains poisonous chemicals like curare (Strychnos toxifera) that has been used as

a paralyzing poison by South American Indians.

Conservators are burdened with decision making in these difficult situations. The

traditional conservation view that is most accepted states: “The conservator’s duty is

to take all possible precautions to prevent or minimize damage to the collection and to

oppose any situation, whether active or passive, that may cause or encourage any

form of deterioration. The welfare of the objects takes precedence over all other

considerations” (Ward 1986, pp 99 - 107).

When we consider the preservation of hazardous materials, however, the safety of

people and their health is the primary concern. The preservation of chemical

substances comes as a second. Every decision must be made separately for each

individual object and all aspects of preservation should be considered before

disposing. This leads to the conclusion that every chemical substance in the museum

collection should be researched and documented. Only based on that knowledge is

correct decision-making possible.

2. What kinds of chemical substances are encountered as historical objects?

Every conservator must first ask what the material of the conservation object is,

before he or she can start practical or preventive conservation. Therefore, the

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question "What?” is a very important and basic one. When the conservation object is

a chemical substance the answer to the question “What?” is more difficult. The

identification of chemicals usually requires some training in chemistry and laboratory

equipment. Some chemicals in museums are in labelled containers but it is always

better to confirm the data by examination. The labelled container may contain some

other substance than the one named on the label, or chemical reactions could occur

in the substances changing the original contents.

2.1. Classification of chemical substances

Chemical substances can be divided in different ways according to their physical or

chemical properties. Each classification helps us recognize unknown substances.

Below are some criteria and their descriptions that can help classify unknown

chemical substances.

2.1.1. Organic and inorganic substances

Basic classification of chemical substances is grouping into organic or inorganic

chemicals.

Organic substances consist primarily of carbon and hydrogen, but may also contain a

number of other elements, including nitrogen, oxygen, halogens, phosphorus, silicon

and sulphur. Organic compounds exist in an extremely large variety. The

classification of organic substances is not possible without having a full description of

the relative arrangement of the atoms within a molecule of the compounds. Other

elements present in hydro – carbon atomic structure are so-called functional groups.

They have a decisive influence on the chemical and physical characteristics of the

compound. Those containing the same atomic formations have similar characteristics,

which may be: solubility in water, acidity / alkalinity, chemical reactivity, oxidation

resistance and others.

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Organic compounds may be aliphatic, where the carbon chain is open or cyclic with a

closed carbon chain. Under those two groups there are many sub-groups that further

classify organic compounds.

Organic compounds often exist as mixtures. Organic mixtures usually dissolve in

organic solvents and separate. There are several methods for separating mixtures of

organic substances like: distillation, crystallization and chromatography.

In contrast to organic compounds, inorganic compounds are oxides, acids, salts,

carbides and minerals. Carbon can also be found in inorganic compounds but only in

simple carbon compounds that do not contain carbon – carbon bonds.

Large groups of compounds in inorganic chemistry are so-called coordination

compounds. A coordination compound is the product of a Lewis acid-base reaction in

which neutral molecules or anions (ligands) bond to a central metal atom (or ion) by

coordinate covalent bonds.

Coordination compounds and complexes are distinct chemical species - their

properties and behaviour are different from the metal atom/ion and ligands from which

they are composed.

2.1.2. Solids and liquids

Resistance to deformation and changes of volume characterizes the solid state of

chemical compounds. Solid state has the following properties:

- The atoms or molecules of solid substances are packed closely together

- The atoms or molecules of solid substances have a fixed position in space

relative to each other. This accounts for the solid's rigidity

- If sufficient force is applied, either of these properties can be violated, causing

permanent deformation

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In liquid state particles of chemical compounds can freely move within the volume of

the container they are confined in. They form a surface that may not be necessarily

the same as that of the container. The volume of the liquid state of a chemical

compound is related to its temperature and pressure. The liquid compound forms a

surface that works as an elastic membrane that is characterized by surface tension.

Surface tension allows the formation of drops and bubbles. The phenomenon of

capillarity is also a result of surface tension.

Liquids generally expand when heated and contract when cooled. Liquids evaporate

on the surface even below the boiling point. Liquids can be mixed forming another

regular liquid or an emulsion or solution.

2.1.3. Acids, bases and neutral substances

Chemical substances can be characterized by their acidity or alkalinity. Those

properties of chemical substances are measured by pH. The Danish chemist S.P.

Sørensen introduced the concept of pH. The pH scale is a reverse logarithmic

representation of relative hydrogen proton (H+) concentration in aqueous solution.

Acids are considered an opposite to bases and can be neutralized by them. Only

weak bases, such as soda, should be used to neutralize any acid spills. Neutralizing

acid spills with strong bases may cause a violent exothermic reaction, and the base

itself may cause just as much damage as the original acid spill.

2.1.3.1 Acids

Chemical compounds that dissolve in water, with a pH of less than 7 are considered

acidic. According to a modern definition by Johannes Nicolaus Brønsted and Martin

Lowry an acid is a compound which donates a hydrogen ion to another compound

called base.

Acids have the following properties:

14

- Sour taste

- Strong acids react aggressively with metals. Acid–metal reactions produce a

salt and hydrogen

- Acids react with metal carbonates to produce water, carbon dioxide and salt

- Acids react with bases to produce a salt and water. This is a so-called

neutralization reaction

- Acids react with metal oxides to produce water and salt

- Acids are electrolytes

- Acids turn moist blue litmus paper red and methyl orange red

- Many concentrated acids are very dangerous. They can cause severe burns

2.1.3.2. Bases

Chemical compounds that dissolve in water with a pH of more than 7 are alkaline.

The bases are substances that can accept protons. Bases have the following

properties:

- Bases have a bitter taste

- Bases deteriorate organic materials

- Bases react with acids (often violently) producing water and salt

- Water solutions of bases conduct electricity

- Bases turn red litmus paper blue

- Strong bases, like strong acids are dangerous. They can cause serious burns

on the skin

2.1.4. Toxic, dangerous and non-hazardous substances

Another way to classify chemical substances is according their effect on a human

being and their environment. In this classification we can speak about toxic

substances that have poisonous properties, dangerous substances that can cause

damage or safe substances.

2.1.4.1. Hazardous substances

15

Hazardous chemicals are chemicals that can harm people, property, or the

environment. A hazardous substance may be radioactive, flammable, explosive, toxic,

corrosive, bio hazardous, an oxidizer, an asphyxiant, a pathogen, or an allergen.

The transportation, use, storage and disposal of hazardous materials is strictly

regulated by law to reduce the risk of injury and disaster. This must be considered

when planning the storage and exhibition of hazardous materials in a museum

setting. People who handle hazardous substances should be trained in all procedures

and precautions required.

There are several EU directives and regulations concerning the use of hazardous

substances issued. The most important is REACH (Regulation (EC) No1907/2006).

All hazardous chemicals should be marked by specific symbols. Appendices 1 and 2

contain valid EU symbols for hazardous materials and other common hazards.

Safety data sheets about hazardous substances are available on the Internet. A large

database can be found on the United States National Library of Medicine Website -

TOXNET. (Hazardous Substances Data Bank 2006)

In Finland all chemicals have their own safe usage data sheet (käyttöturvallisuustie-

dote) that can be found on the following website: www.käyttöturvallisuustiedote.fi

2.1.4.2. Toxic substances

One group of hazardous materials is toxic substances. Toxic substances have an

effect on humans or other living organisms. Toxic substances can cause illness, injury

or death to living organisms. The toxicity may be caused by a chemical reaction or

other activity on molecular scale when a sufficient quantity is absorbed by the

organism. Toxic substances can work rapidly or can cause long-term poisoning when

organisms are exposed to them. When dealing with toxic substances extreme care

should be taken and regulations regarding toxic substances should be followed.

16

When dealing with an unknown chemical substance, all precautions against toxic and

hazardous materials should be taken.

The toxicity of the substance is affected by the method of exposure (dermic, inhaled,

ingested), time of exposure, and number of exposures.

Poisons are usually symbolized by a skull and crossbones symbol. Chemicals that

are non-lethal may be toxic as well, but they are not marked with the same symbol. In

contrast to outright poisonous substances they may be harmful, irritating,

environmentally hazardous, or corrosive.

Toxic substances are seldom used for their toxicity but rather for other chemical and

physical properties.

Three types of toxic substances can be identified:

- chemical toxins

- physical toxins

- biological toxins

Chemicals in museum collections typically represent one of the first two categories.

Biological toxins like bacteria or viruses are not typically collected by museums.

Radioactive materials, under the second category, can be found in museums.

Figure 1. EU standard toxic symbol, as defined by

Directive 67/548/EEC.

17

Chemical toxins may be inorganic like, for example heavy metals, mercury and

hydrofluoric acid, or organic toxins. Most medications are organic toxins, for example

methyl alcohol.

Mixtures of chemicals are more difficult to assess in terms of toxicity than pure

substances and have to be studied carefully. When an unknown mixture is handled,

caution is always indicated.

2.1.4.3. Non-hazardous substances

Non-hazardous substances can be classified as chemicals that are not toxic or

harmful to human beings or the environment in any other way.

Otherwise harmless chemicals can cause damage to museum objects under some

unforeseen circumstances. For example talc, which is a mineral powder composed of

hydrated magnesium silicate, can cause many problems for a conservator when

spilled over an object that is difficult to clean.

2.2. Ageing process

Common sense and chemical intuition suggest that the higher the temperature, the

faster a given chemical reaction will proceed. Quantitatively, the relationship between

the rate of the reaction and its temperature is determined by the Arrhenius equation.

The Arrhenius equation shows the dependence of the rate constant k of chemical

reactions on the temperature T (in Kelvin) and activation energy Ea.

k = Ae – Ea/RT

where A is the coefficient and R is the gas constant.

Chemical substances, just like everything else, age. Three types of ageing can be

recognized: physical ageing, photochemical deterioration and thermal degradation.

18

Ageing reactions for simple chemical substances are probably easier to predict than

for mixtures of substances or objects built of mixed materials.

Conservators’ concern is how to slow the process of ageing and deterioration and

predict the changes in physical and sometimes also chemical properties of materials.

For this reason we should study and understand the process. The contribution of

science to conservation problems is often applied to the examination of the museum

object but rarely to the investigation of material deterioration and preservation of

objects. This is most probably because the ageing process is very difficult to simulate

in a laboratory. The Arrhenius equation can be applied to the kinetics of chemical

transformation; the complex properties of many museum artefacts that are registered

during accelerated ageing cannot be simply related to their chemical composition.

Therefore testing some materials for accelerated aging will not always be related to

the natural aging of the artefacts. Only under certain conditions is the Arrhenius

equation applicable. (Zou 1996, pp 243 – 267).

For example, studies of the accelerated ageing of photographic materials prove that

the Arrhenius equation can provide valuable information if the degradation process at

elevated temperature proceeds by the same mechanism as at the storage

temperature. (Adelstein 1997, pp. 193 - 206).

Figure 2. Modes of oxygen

uptake versus time (according

to Feller 1994, pp 91-99).

19

For chemicals in museum collections predicting the ageing process can seem less

complicated when the chemical in question is common. The Arrhenius equation

should give the information about the aging reaction. The situation may, however, be

more complicated when the substance contains impurities or if it is a mixture.

According to the Arrhenius equation, lower temperature slows chemical reactions and

hence slows ageing. However, low temperatures can also have a negative effect on

some chemicals causing some physical changes like crystallization (olive oil).

In Figure 2, Feller proposes four basic ways of deterioration of organic substances.

The ageing process is rarely linear and changes in the properties of substances

seldom proceed at a steady rate (Fig 2a) but usually occur in stages.

The ageing often speeds up (Fig. 2b) or slows down (Fig. 2c) over time. The last chart

(Fig. 2d) presents a situation where in the beginning ageing accelerates and then

decelerates. The type of deterioration process presented in Fig. 2d can be very

difficult to study. In this type of deterioration there is a time at which no observable

changes occur in chemical or physical properties. That time is called induction time.

Only after the induction time is over can deterioration be observed. Conservators

should be very wary of that type of ageing because after the induction time, changes

in substances can be very rapid.

Recognizing the degradation profile of substances helps us estimate the possible

changes and the speed of the ageing process. This knowledge is very useful in

planning preventive conservation and, if possible, should be studied in a laboratory

utilizing accelerated ageing. Laboratory studies of the ageing process should attempt

to answer the following questions: Why do the physical changes occur? Can they be

avoided? How to slow the ageing process? Before good prevention practices and

treatment methods can be developed, it is necessary to study the ageing and

degradation processes of chemicals in museum collections. Only then can effective

conservation techniques can be applied.

20

2.3. Changes in the physical properties of chemical substances

Chemical substances have properties that help us identify them. These properties are

physical or chemical. Physical properties do not change the chemical nature of

matter.

The more properties we can identify for a substance, the better we know the nature of

that substance. These properties can then help us model the substance and thus

understand how this substance will behave under various conditions.

Any aspect of a chemical substance that can be measured or perceived without

changing its identity is called a physical property. Below are listed some of the

physical properties of chemical substances: absorption, colour, concentration,

conductivity, density, dimensions, freezing point, boiling point, melting point, smell,

spectrum, weight, opacity, viscosity, and volume.

2.3.1. Changes in the state of matter

Chemical substances can be observed in three basic states of matter: solids, liquids

or gases. Every state of matter has typical physical attributes that differentiate that

state from the others. For example, liquids and gases do not have dimensions or

shapes. They are distinguished from each other in the way that gases are always

soluble in each other while two liquid phases may be insoluble (for example: water

and oil).

Chemical substances can change their state of matter. Different factors can cause

that change. However, the transformation of the state of matter is always connected

with energy.

Common transformations of the states of matter are:

- Melting – freezing (liquid – solid)

21

When the internal energy of a solid is increased, usually by heat, to a melting

point it will change its physical phase to liquid. The opposite reaction is called

freezing.

- Evaporation – condensation (liquid – gas)

During evaporation molecules of liquid become gaseous. Evaporation occurs

without the liquid being heated to boiling point. Liquids evaporate because their

molecules are in motion in random directions and that kinetic energy is enough

for the molecules to “fly off” the liquid surface. Evaporation rates differ for

different liquids. Some liquids are more volatile, like ether and others seem not

to evaporate at all, like oils.

The evaporation of a substance is affected by the concentration of the

substance in the air, temperature, ventilation, and the area of the evaporation

surface.

- Sublimation – deposition (solid – gas)

Most chemical substances possess three different states at different

temperatures and the transition from solid to gas state goes through liquid

state. In some cases the transition from solid to gas is so rapid that no liquid

state can be observed. This process is called sublimation and the opposite

process deposition.

Examples of chemicals that can sublimate are: zinc, cadmium, iodine,

naphthalene, and arsenic (at high temperatures).

In the diagram below (Figure 3), pressure is presented on the Y-axis, and

temperature on the X-axis. The triple point is the temperature where the three states

(solid, liquid, gas) co-exist.

If the pressure is above the triple point the substance behaves as follows. A

substance is a solid at low temperature and at a given pressure. When the

temperature rises it reaches a point at which turns into a liquid. This is called the

melting point. If the temperature of liquid rises further it eventually reaches a

22

temperature at which it turns into a gas. This is the boiling point. When the pressure is

below the triple point the following happens: The substance is a solid at lower

temperatures. When heated the substance changes directly into a gas. This process

is called sublimation and the temperature at which the change in the state of matter

occurs is called the sublimation point.

The melting, boiling and sublimation points of a substance depend on the pressure.

Changes in the polymorphic phases of chemicals in museum collections are mostly

caused by temperature changes. Temperature changes can cause non-crystalline

chemicals to transform into crystalline form. This phenomenon can be observed, for

example, in olive oil at low temperatures.

According to Ellen Pearlstein:

"Fats and waxes, which are semi-solid at room temperature, will continue to respond

to subtle temperature changes with phase transitions, reaching a new equilibrium at a

new temperature … a varied temperature history and the inclusion of impurities in a

sample would make predictions of polymorphic behaviour almost impossible”.

(Pearlstein,1986, pp 83-91).

Figure 3. Triple point of

three existing phases.

23

Some metals can exist in different allotropes that can be affected by temperature, for

example, tin. Beta tin allotrope at room temperature is a white metal but when the

temperature decreases alpha tin allotrope in the form of grey powder, becomes more

stable. That phenomenon affected Napoleon’s invasion of Moscow in 1812 when

soldiers’ buttons disintegrated. (Carrlee 2003, pp 141 -116).

2.3.2. Hygroscopic properties and reactions with water

Water in the form of moisture is present in our environment and greatly affects all

artefacts in museum collections that are hygroscopic or have the ability to react with

molecules of water.

Some chemical substances, like most organic materials and minerals are

hygroscopic. This means that they have the ability to absorb and desorb molecules of

water from the surrounding environment. Absorption and desorption of moisture

depend on the temperature and humidity conditions of the surrounding air.

Hygroscopic substances include glycerine, ethanol, methanol, and honey. Absorbing

water can change the physical and chemical properties of chemical substances.

Some chemicals, especially salts, are very hygroscopic. They can absorb large

amounts of water from the atmosphere and form liquid solutions. They change their

state of matter. Such chemicals are called deliquescent. The following are examples

of deliquescent compounds: calcium chloride, magnesium chloride, zinc chloride, and

sodium hydroxide.

Because of their affinity for atmospheric moisture hygroscopic substances should be

stored in sealed containers.

When assessing the risk to hygroscopic chemicals in museum collections

environmental conditions of the storage or exhibition space should be described and

controlled.

24

Examples of hygroscopic materials that can cause problems to a conservator are

sugar and honey. There are many museums that collect decorative objects

containing sugar. The British Museum has a collection of sugar artefacts made in

Mexico for the celebration of the Day of the Dead (2nd of November). These artefacts

were collected in 1986. Just one year afterwards some white areas were yellowed.

This discoloration was caused by the deterioration of sugar due to hydrolysis. V.

Daniels and G. Lohneis explained the mechanism of sugar hydrolysis and its

discoloration. (Daniels 1997, pp.17 – 26).

Hydrolysis of sugar, i.e. its reaction with water, can convert sucrose into a syrup of

fructose and glucose, producing so-called invert sugar which is brownish in colour.

2.3.3. Sedimentation and separation of chemical substances

Chemicals that are in the form of a solution or suspension can sediment and

separate. Sedimentation is a phenomenon of motion of the molecules in a chemical

substance that is caused by an external force like gravity. Sedimented chemicals that

were supposed to be in one physical phase can be in two phases (liquid and solid).

Sedimentation can be difficult to observe if the mixture ingredients are in the same

physical phase. Only further examination of chemical properties can confirm the

separation.

Sediments can be divided into three groups:

- Mechanical

Chemicals in suspension can separate because of the gravitational force and

deposit at the bottom of the container.

- Chemical

Chemical sediments are formed by chemical reactions.

- Organic

Organic sediments are formed as a result of actions performed by biological

organisms.

25

2.4. Changes in chemical properties

Chemical properties define the chemical nature of the substance. Chemical properties

are characteristics under certain conditions (temperature, atmospheric pressure).

Chemical properties become apparent during chemical reactions and are observed as

a change in the chemical identity of the substance.

Examples of chemical properties are: heat of combustion, reactivity with water, PH,

electromotive force, toxicity, stability, reactivity to other chemicals, and flammability,

Chemical changes result in one or more substances of a different composition being

created from the original substances. The atoms in the compounds are rearranged to

make new and different compounds.

Below are typical reactions that may occur in chemical substances.

- Synthesis

A + B AB

- Analysis (decomposition)

AB A + B

- Substitution (single displacement)

AB + C AC + B

- Double displacement

AB + CD AC + BD

- Chemical equilibrium

Chemical reactions result in chemical changes. For chemical substances that are in

museum collections they are always undesirable.

2.4.1. Oxidation reaction

The term oxidation was originally derived from the observation that almost all

elements react with oxygen to form compounds called, oxides. Now the scope of the

26

term has been extended and includes any reaction in which electrons are transferred.

This type of reaction is called redox (reduction – oxidation).

Oxidation and reduction always occur simultaneously. The substance that gains

electrons is called the oxidizing agent and the substance that loses electrons the

reducing agent.

Common oxidants are: oxygen, halogens, potassium permanganate, potassium

dichromate, and nitric acid. Common reductants are: metals, hydrogen, hydrogen

sulphide, carbon, carbon monoxide, and sulphurous acid.

Aniline serves as an example of an oxidation process. The collection of the Police

Museum in Tampere contains bottles of aniline that were used for producing a

reagent for testing diesel oil. The method was used by the traffic police for testing

diesel cars. Some were using fuel oil for its lower cost. The procedure is illegal

because the tax for fuel oil is lower than for diesel.

Aniline is normally colourless but it slowly oxidizes in air, changing colour to red-

brown. The aniline that is now in the Police Museum collection is about 40 years old

and very dark in colour. It can be expected that with time it will finally convert into a

resin. (Morrison R.T. 1992)

2.4.2. Changes in colour

Every chemical substance absorbs a characteristic set of wavelengths of light. This is

the so-called absorption spectrum and can be used to identify the chemical. When the

chemical substance is altered in a chemical reaction its absorption spectrum will

change and so the created product will tend to be of a different colour.

Colour change is not always caused by a chemical reaction, because a compound’s

absorption spectrum is not the only factor affecting its colour. As an example, zinc

oxide changes colour from white to yellow when heated. Colour changes are caused

27

by holes and other defects that are created in the zinc oxide lattice and not by a

chemical reaction.

The aniline in the Police Museum serves as a good example of colour change.

Colour changes can also be observed in another chemical from the same collection.

White or almost transparent silver nitrate gets darker with time. The present, about 40

years old silver nitrate is greyish in colour.

2.4.3. Changes in odour

Humans can perceive volatilized chemical compound with their sense of smell. That

sensation is called an odour or smell and may be pleasant or unpleasant.

Organic compounds produce most of the odours although some inorganic chemicals,

for example ammonia or hydrogen sulphide, have characteristic odours as well.

Objective measure by the human nose is not possible because of the differences in

sensitivity and because of the psychological aspect of smelling sensations.

For most people odour gives little information about chemical substances and the

information is unreliable. Well known odours like alcohol, ammonia or petrol can

provide some knowledge of what we have in the container.

The intensity of odours can be classified and documented. Below is a typical scale of

describing the intensity of odour.

Odour intensity

0 - no odour

1 - very weak (odour threshold)

2 - weak

3 - obvious

4 - strong

5 - very strong

6 - intolerable

28

2.4.4. Precipitation

Formation of precipitate in a solution may occur as a result of chemical reactions.

This happens when, during a chemical reaction a solution is supersaturated by the

compound formed. In most situations precipitate moves to the bottom of the container

due to gravity. Precipitation is often a sign of chemical changes in a solution.

2.4.5. Predicting chemical changes

Most chemicals in museum collections are mixtures. Reactions between the

ingredients of the mixture must be carefully studied todelay the deterioration process

and eliminate unexpected and dangerous reactions. To help predict the ageing

process of a mixture of chemicals it is useful to make a chemical interaction matrix

that considers potential consequences of chemical reactions between the

components. Whether two chemicals react, or react violently, may depend on

temperature, concentrations, impurities, or a number of other factors that are not

always readily understood or explained. In addition, chemicals may interact not only

with one another but also with their environment, including container, air or water and

other materials.

(http://www.hss.doe.gov/healthsafety/wshp/chem_safety/).

Below is an example of a chemical interaction matrix where two ingredients of the

mixture, container material, and environment are taken into consideration. The matrix

is filled with data collected from specialized sources, enabling conclusions about the

interactions between the factors studied. This kind of matrix may be added to the

conservation documentation, providing further information when planning the

preservation and storage of the object.

Some data on the compatibilities of chemicals can be found in an online database of

hazardous materials, CAMEO chemicals, http://cameochemicals.noaa.gov/. Making

the interaction matrix can be very useful in predicting possible reactions and changes

29

in chemical substances and planning preventive conservation of chemicals and their

storage environment.

Table 1. Generic Chemical Interaction Matrix

Chemical 1 Chemical

2

Glass Rubber Air Water Temperature

Chemical 1 X X X X X X XChemical 2 X X X X X XGlass X X X X XRubber X X X XAir X X XWater X XTemperature X

2.5. Effects of mould growth on chemicals in museum collections

Moulds and fungi can be found everywhere. They can grow on almost any substance

when the environmental conditions are appropriate. The presence of moulds can be

determined visually or by microscopic examination. Musty, earthy smell can also be

an indicator of moulds. If they are not visible or cannot be smellt, the presence of

mould can be determined by a laboratory test, letting a sample grow under controlled

conditions.

A very useful tool for determining the danger of mould growth on organic materials is

the so-called “Preservation Calculator“. This is a computer programme that can

estimate days when mould will grow, give approximate aging rates and preservation

indices when given the storage temperature and humidity. It is a good tool when

planning storage conditions for organic materials. It can be especially useful when the

danger of mould growth is present.

30

Figure 4. Preservation Calculator

Preservation Calculator can be downloaded from:

http://www.imagepermanenceinstitute.org

Mould growth is very dangerous to objects in museums, because it can impair organic

materials. It is also very dangerous to museum staff because of potential adverse

health effects. Mould growth on chemicals can also be dangerous for a unique

reason. Mould can change chemicals, making them volatile and causing them to

become airborne.

Recent research suggests that Napoleon’s death was probably caused by fungus.

Napoleon’s hair contained a small amount of arsenic, which would suggest a slow

poisoning of the Emperor. It was concluded that Comte de Montholon murdered

Napoleon for personal reasons. A more probable explanation is the wallpaper from

Longwood House on St. Helena Island. The wallpaper contained Scheele's Green

pigment. This pigment was copper arsenide that becomes toxic in damp conditions

because fungus growing on the paper excretes the poison as arsine gas. The

pigment was widely used in the Victorian era and there are many examples of arsenic

poisoning caused by that pigment. (Ledingham 1994).

31

2.6. Researching physical and chemical properties

The more properties we can identify for a substance, the better we understand its

nature. These properties can then help us model the substance and thus understand

how it will behave under various conditions.

For monitoring the ageing process, changes of one or a few distinguishing properties

of a chemical substance will yield useful information about suspected reactions.

The National Institute of Standards and Technology is a very useful source of

physical and chemical data on specific compounds. That data can be compared with

the results of testing a chemical substance. (http://webbook.nist.gov/chemistry/).

Various wet or instrumental analyses can be used for the identification of unknown

substances or for recognizing changes that may occur during the ageing of chemical

substances. The vast amount of literature on instrumental chemical analyses can be

a first step in making decision about the method used to analyse an unknown

chemical substance.

Electromagnetic spectra obtained by instrumental analysis methods are compared for

identification with existing spectra of known substances. There are many sources of

spectra of known substances. One of them is available on the Internet: The infrared

and Raman spectra database provided by Infrared and the Raman Users Group.

(http://www.irug.org/).

In this chapter the most common instrumental analysis methods are presented,

underlining the methods used during the conservation of chemicals from the

collection of The Police Museum in Tampere.

Table 2 presents the most commonly used instrumental analysis methods and the

information that can be collected from them.

32

Table 2. Most commonly used instrumental analysis methods

Method What is it useful for?

Wet chemistry Wet chemistry techniques that are performed in the liquid phase. They can be used for qualitative and quantitative chemical measurements, such as: pH measurement, viscosity, conductivity. Wet methods can be used for the identification of ions.

VIS spectroscopy Used in the quantitative determination of solutions of transition metal ions and highly conjugated organic compounds

FTIR spectroscopy Qualitative and quantitative analysis of organic substances.

NIR spectroscopy Qualitative and quantitative analysis of organic substances.

Raman spectroscopy Identification of chemical bonds and molecules. It can also identify the crystallographic orientation of a sample and is useful in the identification of inorganic substances and minerals.

X-ray fluorescence Used for elemental analysis and chemical analysis, particularly in the investigation of metals, glass, ceramics

X-ray Absorption Near Edge

Structure (XANES)

Used for elemental analysis and determination of oxidation level

Laser methods Analysis of organic and inorganic compounds

Gas chromatography Analysis of substances containing many organic compounds

Liquid chromatography Method for separating a mixture of chemical compounds

33

2.6.1. Sampling

Sampling a chemical substance that is a museum object must be carefully

considered. The first question is if the container of the substance has ever been

opened. Some chemicals in museum collections are still in their original sealed

containers.

In Saint-Mere-Eglise there is an Airborne Museum with many medicines and other

chemicals that were a part of the equipment of American parachutists dropped into

France in June 1944. Most of them are still in their unopened containers. Similar

collections can be found in many war memorial museums.

Photo 1. Ossuarive de

Douaumont at Verdun, France.

Medical equipment from the First

World War.

Photo. 2. Airborne Museum at

Saint-Mere-Eglise, France.

Some of chemicals that were in

American parachutists’

equipment.

34

When containers are sealed it is probably best to accept that they contain the

substance that is written on the label. It is, however, necessary to study the

substance’s chemical and physical behaviour to ensure correct storage and to plan

preventive conservation.

Photo 1 represents a medical case with seven small vials that contain: ether, cocaine,

sparteine, ergotinine, caffeine, and morphine. The vials are sealed and there is no

reason to open them for research. Emptying the vials could be considered because of

the sensitive. Two of them contain illegal drugs. The exhibit should be very well

secured.

Unsealed containers, especially if they are not labelled, should be analysed (Photo 3).

Most analysis methods require a very small sample and some of the samples can be

recovered after analysis. Sampling unknown substances should be done cautiously

and all possible precautions should be taken when opening containers and taking

samples. This procedure is best done at a chemistry laboratory where protective

equipment is available.

Photo 3. Memorial Museum at Caen, France. Some medical equipment from

a German field hospital.

35

2.6.2. FTIR spectroscopy

Figure 5 presents a full electromagnetic spectrum with the range of all possible

electromagnetic radiation. The electromagnetic spectrum of a substance is the

characteristic distribution of electromagnetic radiation from that object.

IR spectroscopy, meaning spectroscopy in the infrared region (4000 – 500 cm -1) is

most useful for the analysis of organic compounds and some inorganic substances. It

can also be used when analysing substances in a mixture; however, the best

identification results are achieved when the mixture is first separated. FTIR

spectroscopy will not accurately identify mixture ingredients that are less than 10% of

the mixture.

Photon energies associated with the infrared region are not large enough to excite

electrons, but may induce vibration of covalently bonded atoms and groups. All

organic compounds will absorb infrared radiation that corresponds in energy to these

vibrations, either by stretching, bending or rocking. Infrared spectrometers are

permitted to obtain absorption spectra of compounds that are a unique reflection of

their molecular structure. Detailed information about the infrared absorptions

observed for various bonded atoms and groups is usually presented in tabular form.

Appendix 4 provides a collection of such data for the most common functional groups.

Figure 5. Electromagnetic spectrum.

36

FTIR has different modes (transmission and reflection) that can analyse spectra from

various types of samples. Today's FTIR spectrophotometers are computerized, which

makes them faster and more sensitive than the older instruments. There also exist

wide IR-spectra databases that are used for comparison.

FTIR spectrophotometers are most useful for identifying types of chemical bonds and

functional groups of substances. The wavelength of light absorbed is a characteristic

of the chemical bond and based on this the compound can be identified. For most

common materials, the spectrum of an unknown material can be identified by

reference to a library of known compounds. To identify less common materials, IR will

need to be combined with other techniques.

In addition to qualitative analysis, FTIR can provide a quantitative analysis of a

mixture, because the strength of the absorption is proportional to the concentration of

a chemical. (http://orgchem.colorado.edu/. 2008)

2.6.3. NIR - Near Infrared Spectroscopy

NIR spectroscopy is spectroscopy in the near infrared region, from 800 nm to 2500

nm. This method can be used for qualitative and quantitative analysis. Because

electromagnetic penetration for near infrared waves is deeper than for IR, analysis of

samples in a glass container can be performed without the need to open it.

2.6.4. X-Ray Fluorescence Spectroscopy

The X-ray fluorescence is an analytical technique based on the interaction between

X-rays and the substance under analysis to determinate its elemental composition.

XRF is suitable for solids, liquids and powders. It is applicable over a wide range of

concentrations, from 100% down to parts per million. XRF is very well suited for fast

qualitative elemental analysis. Normally it can identify elements from sodium to

uranium. It does not need any special sample preparation. The XRF method can also

37

be used for quantitative analysis because the peak height for any element is directly

related to the concentration of that element. (http://www.amptek.com/xrf.html. 2008)

XRF method is non-destructive and can be used in situ. When a radioactive photon

from an x-ray tube or a radioactive source strikes a sample, the X-ray can either be

absorbed by the atom or scattered through the material. When an X-ray is absorbed

by the atom it transfers all of its energy to the innermost electron. During this

process, if the primary X-ray has sufficient energy, electrons are ejected from the

inner shells, creating vacancies. These vacancies present an unstable condition for

the atom. As the atom returns to its stable condition, electrons from the outer shells

are transferred to the inner shells and in the process gives off a characteristic x-ray

whose energy is the difference between the two binding energies of the

corresponding shells. Because each element has a unique set of energy levels, each

element produces x-rays at a unique set of energies, making it possible to non-

destructively measure the elemental composition of a sample. (Knuutinen. 2006, pp 1

-85).

2.6.5. X-ray Absorption Near Edge Structure (XANES)

XANES is X-ray absorption spectroscopy used for the identification of substances. It

is most useful for determining the oxidation state of elements. It is also used to

determine the proportions of each compound in a sample.

2.6.6. Raman spectroscopy

Raman spectroscopy is widely used in chemistry for the identification of chemical

bonds and molecules. It gives characteristic spectra for organic molecules in the

range 500 –2000 cm-1. It can also identify the crystallographic orientation of a sample

and is useful in the identification of inorganic substances and minerals. Raman

spectroscopy is a non-destructive analytical method and the instrument used can be

portable. Raman spectra can be collected from a very small sample (< 1 µm in

38

diameter). Raman spectroscopy is suitable for the identification of minerals, polymers,

and proteins.

2.6.7. Laser methods

There are several laser methods that are used for the chemical analysis of inorganic

and organic compounds, like:

- LIBS (Laser Induced Breakdown Spectroscopy). This technique offers

qualitative and quantitative elemental analysis with a spectral range of 200 -

980 nm. The method can be used for the identification of inorganic substances.

- LIF (Laser Induced Fluorescence). This method can be used for analyzing

inorganic and organic substances.

- LA-ICP-MS (Laser Ablation Inductively Coupled Plasma Mass Spectrometry) is

a very sensitive analytical method for rapid multi-element determination in the

trace range of inorganic solid sample materials. (Kolar, Strlič, 2007)

2.6.8. Chromatography methods

Chromatography is a separation method that uses differences in partitioning

behaviour between a flowing mobile phase and a stationary phase to separate the

components in a mixture. After separation sample components are analysed.

- Gas chromatography is used for volatile organic compounds.

- High-performance liquid chromatography separates analytes based on polarity

- Liquid chromatography is used for separating ions and molecules that are

dissolved in a solvent.

- Size-exclusion chromatography is a separation method in which particles are

separated according to their size. SEC is used for the analysis of synthetic and

biological polymers.

- Thin-layer chromatography, a simple and rapid method for separation of

organic compounds.

39

2.7. Molecular Diversity Preservation International

Molecular Diversity Preservation International (MDPI) is an organisation for the

deposit and exchange of molecular and bio-molecular samples.

(http://www.mdpi.org/).

The MDPI is a non-profit organization in Switzerland. Its mission is to preserve

historically significant chemical samples in the Chemical Museum in Basel.

The organisation also participates in sharing and exchanging rare chemical samples

for research purposes.

If a museum has some rare chemicals but is unable or unwilling to store them, it can

deposit them at the MDPI. Samples should be stable at room temperature, pure and

non-hazardous. The quantities of deposits are from 10 mg to 100 g. Samples of

chemicals can be also borrowed for chemical, non-destructive use.

2.8. Documentation of chemical substances in a museum

Documentation of artefacts is very important for conservation. Using knowledge

gathered in documentation and during the historical and physical research of the

artefact, conservators can better make their decisions concerning the object. The

documentation of the artefacts is also a very important tool for communication both in

the present and in the future. Documentation has three important roles: it can be used

instead of the real object for historical research, it contains the known history of the

artefact and it helps safeguard the artefacts because it contains storage instructions.

All information gathered in the artefact’s documentation should be reliable and their

sources cited. (Häkäri. 2001).

In the documentation of chemical substances in museum collections conservators

should include in addition to aspects that are usually included in artefact

documentation, chemical analysis, safety instructions and information for the safe

40

handling and storage of chemicals. For drugs whose possession is regulated by law,

the required document should also be attached as well.

The documentation of chemical substances should include:

1. description of chemicals: container and chemical

2. origin of the chemical substance

3. ownership and history of ownership

4. identification, knowledge and description of what it was used for and by whom

5. condition

6. possible conservation report

7. safety instructions for handling and storage and possible dangers that can be

caused by the chemical

8. photographs of the artifact

3. Chemicals in the Police Museum collection in Tampere, Finland

As empirical research of a chemicals collection, I studied the collection of the Police

Museum in Tampere.

In 1995, the Ministry for Internal Affairs in Finland started a project that surveyed

historical police material from all municipalities in Finland. The museum material was

inventoried and in 2003 the decision about the establishment of a national Police

Museum was taken. The Police Museum was established in 2004.

Chemicals that were found in the collection of the Police Museum in Tampere were

donated by the Police Technical Centre from Helsinki and by the Traffic Police

Department.

3.1. Where do they come from?

Most of the museum collection comprises artefacts from the Police Technical Centre

and artefacts that concern the Traffic Police Department.

41

In the group of objects that belonged to the traffic police are two interesting field

laboratory bags from the 1960s. The chemicals from those bags were used for testing

diesel oil. In Finland the tax on fuel oil was lower than on diesel oil, and therefore

some people used it instead diesel oil or mixed the two. The fuel oil was not coloured

as it is nowadays and was difficult to recognize without chemical testing. The field

laboratory bags contain chemicals that were used for identifying fuel oil. Two

reagents, aniline and acetic acid, were used. The reagents were mixed and added to

the tested oil. If the sample contained fuel oil instead of diesel, a dark red circle was

formed between the oil and the reagent. If the sample contained a mixture of fuel and

diesel oil the red circle was not so clear. Pure diesel oil gave no reaction. If there was

a reaction and the traffic police suspected the use of illegal fuel oil in the vehicle or

other engine, the sample was sent to the Laboratory of the Customs Department for

further investigation. The Laboratory of Customs Department belongs to the Tax

Office which controls the taxation of fuel.

Lappalainen in his interview explained about preparing the reagent for testing fuel oil.

He raported that the required chemical reagents, aniline and acetic acid, were bought

from a pharmacy and mixed before testing at the police station. He remembered that

prepared reagents were useful for only a few days. When old, white crystals were

formed on the bottom of the reagent container and the expected reactions did not

occur. The containers with dark liquid and white crystals were found in the field

laboratory bags deposited at the Police Museum likewise test tubes with tested

samples. (Lappalainen 2007).

Below is a text translated from Finnish, found in one of the field laboratory bags

explaining the preparation of the reagent and testing the sample of suspected oil.

The second group of chemicals found in the Police Museum in Tampere are

chemicals from the Police Technical Centre. These chemicals were used for crime

investigation and photographic purposes. The purpose of some of the chemicals is

very difficult to guess.

42

Information about some of the chemicals was provided by Ilkka Sjöman of the Police

School in Tampere.

That group of chemicals included:

- Iodine used for developing fingerprints on paper

- Chemicals like Malachite Green, Fuchsine used for colouring samples

investigated under a microscope. According to Sjörman, Fuchsine was

sometimes used as a “trapping colour” for objects that might be stolen.

- Silver Nitrate used in photography

There are also solvents used in a laboratory like acetone, aseptic liquid – Neo-

amisept, but also chemicals whose use is unknown like “siansappi viinan “ that

can be translated into English as “pig’s bile in ethanol”.

3.2. Present condition and storage of chemicals at the Police Museum in Tampere

Before the conservation evaluation and treatment chemicals received from Helsinki

Police Technical Centre and Traffic Police Department were stored in a temporary

storage place together with other artefacts. They did not have their own separate

storage space and no safe storage containers. Chemicals were stored in their original

containers and bottles. Some of the containers or their lids were damaged (Photo 4

and Photo 5). Placement of the containers was not planned and some dangerous

chemicals like a strong oxidizer - silver nitrate could be placed close to flammable

acetone.

Most of the chemicals were in small containers that were packed in open cardboard

boxes. The cardboard boxes did not give sufficient protection if some of the chemical

containers were broken.

Chemicals used in field testing by traffic police were stored in their original containers

placed in bags, the same way as during their lifetime (Photo 6). Some of the

chemicals used for testing diesel oil were dangerous. In one of the field laboratory

bags, two testing tubes with unknown liquids were found (Photo 7). The field

43

laboratory bags were made of cardboard and their inner surfaces were covered with

paper in one case and with PVC film in another. Both surface materials could be

easily irreparably damaged if aniline or acetic acid made to affect them.

Photo 4. Damaged container

with silver nitrate from the

collection of the Police

Museum.

Photo 5. Bottle of aniline

with damaged lid, from

the collection of the

Police Museum.

44

Photo 6. Field equipment bag of chemicals for testing the purity of gasoline. From the

collection of the Police Museum.

Photo 7. Test tubes with unknown

liquid found in one of the mobile police

field bags for testing the purity of

gasoline. Police Museum collection.

45

3.3. Types of chemicals in the collection of the Police Museum in Tampere and their

characteristic.

There are thirty-four chemicals in the collection of the Police Museum in Tampere that

can be grouped and characterized in different ways. Some bottles contain the same

chemicals.

There are eight solid chemicals and twenty two liquids. There are also samples that

are liquid but contain crystals.

Nr Name of chemical, taken from label State

1 Anthracene Technical solid

2 Zinc Silicate solid

3 Argent. Nitr.Ph.F.VI (hopeanitraatti) solid

4 1-Naphthylamine-4-sulphonic acid solid

5 Peroxide, 3% liquid

6 Paraffin liquid

7 Glycerin liquid

8 Acetone liquid

9 Neo-amisept liquid

10 Malachite green solid

11 Fuchsine solid

12 Tetrabromphenolsulfophtalein solid

13 Clove oil liquid

14 Iodine solid

15 Iodine + sol.calc.chloride cntr liquid

16 Unknown, labelled in Finnish :

Siansappi viinan

liquid

17 Acetic acid liquid

18 Aniline liquid

Table 3. Labelled chemicals from Police Museum collection.

46

Table 3 presents the full list of chemicals that are in their original containers with

labels.

There are also seven containers containing unknown liquid substances. All the

unknown chemicals were found in the field laboratory bags for testing fuel oil.

3.4. Identification of chemicals from the collection of the Police Museum in Tampere

The conservation process and decision-making concerning chemicals from the Police

Museum in Tampere was preceded by researching of the objects that could help

identify unknown substances and confirm labelled ones.

In analysing chemicals the methods available to EVTEK Design Institute,

Conservation Laboratory were used. The main research tool was the FTIR

spectrophotometer that helped to analyse most of the organic substances. The acidity

of unknown chemicals was measured by pH-meter and elemental contents of solid

chemicals defined by XRF. Other physical parameters were described using

organoleptic methods.

3.4.1. Description of conservation objects

In the description of conservation objects, both containers and chemicals were

described. Table 4 lists chemicals obtained from the Police Technical Department of

Helsinki. Table 5 and Table 6 present chemicals from field laboratory bags obtained

from the Police Traffic Department. Most of the chemicals in Tables 5 and 6 are

unknown.

Table 4. Chemicals from the Police Technical Department of Helsinki.

Nr Label Description1. BDH Anthracene Technical The British

Drug Houses Ltd. London 20082191:4701 250 Grams

Chemical:Gray powderQuantity: about 100 ml

47

Container:Dark brown glass container with black plastic screw top.Dimensions: height: 15 cm, diameter: 7 cm

2. BDH Zinc Silicate made in England The British Drug Houses Ltd. B.D.H. Laboratory Chemicals Group Poole England

Chemical:White-grayish powderQuantity: about 50 mlContainer:Dark brown glass container with black plastic screw top.Dimensions: height: 12 cm, diameter: 6,5 cm

3. ..mpereen Rohdos Oy Helsinki 250,0 Argent. nitr. Ph. F. VI. …mmerfors Drog Ab Helsingfors” and ”Hopeanitraatti” which means silver nitrate

Chemical:Hardened grayish powder.Quantity: about 100 mlContainer:Dark brown glass container with black plastic screw top.Dimensions: height: 9,5 cm, diameter: 6 cm

4. “BDH laboratory reagent, 1-Naphtylamine-4sulphonic Acid NH2C10H6 SO3Na4H2O=317,32 (Naphthionic acid) Purified sodium salt, made in England, The British Drug Houses Ltd. B.D.H. Laboratory Chemicals Group Poole England 668308/520222 100 g net” and second one “ Tuonti-import Rohdoskeskus Oy Drogcentral Ab Helsinki-Helsingfors Puh. 65806 Tel”

Chemical:White powderQuantity: 20 mlContainer:Dark brown glass container with black plastic screw top.Dimensions: height: 11 cm, diameter: 5,5 cm

5. “Vätesuperoxidlösning 3% Till sårbehandling outspädd, till gurgling utspädd med 3-5 deler vatten Apoteket Hjorten Västerås”

Chemical:Transparent liquid.Quantity: about 100 mlContainer:Dark brown glass bottle with black plastic screw top. Dimensions: height: 18 cm, diameter: 6,5 cm

6. „Gdanski Zarzad Aptek Laboratorium Chemical:

48

Goleniowe Ilosc 200 g, Cena z opak. 6,90, Parafina oczyszczona F.P.III, wewnetrzne Nr serii 440459”

Thick transparent liquid. In liquid fragments of natural cork and unknown plastic (?) film can be found.Quantity: about 50 mlContainer:Bluish glass bottle with grey rubber top. Dimensions: height: 19 cm, diameter: 6 cm

7. “Runeberg Runeberink.25 Puhelin 42640 Glyseriiniä Glyserin A/b Erna O/y”

Chemical:Thick transparent liquid. Quantity: about 20 ml Container:Bluish glass bottle with red plastic screw top. Dimensions: 14,5 cm x 6 cm x 2 cm

8. a. Three labels: ”Kruunuhaan uusi apteekki Snellmanink. 13 Puh. 665500, 625500, Asetonia Aceton”,”Ulkonaisesti Utvärtes””tulenarkaa eldfarligt LKKL”

b. Two labels: ”Willhelmsin apteekki, Asetonia Aceton Ulkonaisesti Utvärtes Willhelms Apotek” and ”tulenarkaa eldfarligt”

a. Chemical:Transparent liquidQuantity: about 4 mlContainer:Dark brown glass bottle with black plastic screw top.Dimensions: height: 10 cm, diameter: 3,5 cm

b. Chemical:Transparent liquidQuantity: about 10 ml.Container:Dark brown glass bottle with black plastic screw top.Dimensions: height: 10 cm, diameter: 3,5 cm

9. ”Neo-Amisept desinfioimisaine – desinfektionsmedel Sisältää 0,2% suurimolekyylistä dialkyylimetyyliammoniumkloridia – Käytetään laimentamattomana ihon desinfiointiin ennen lääkintätehtäviä,

Chemical:Transparent liquidQuantity: about 100 ml.Container:Glass bottle with white plastic screw top.

49

puoleksi vedellä laimenettuna ihon pyyhkeisiin ja haudekääreisiin. Neo-Amiseptilla on hyvä rasvanliuotuskyky ja liuotin haihtuu iholta nopeasti. Se soveltuukin erinomaisesti käytettäväksi spriin tai eetterin asemasta ja on näitä tehokkaampi. Ei sekoiteta saippuaan. Vaarallista nautittavaksi. Tulenarkaa 1lk., 200 ml, Lääke Oy”

Dimensions: height: 16 cm, diameter: 5 cm

10. Two labels: “1397 100 g Malachitgrün, konzentriert, Malachite-Green, Made in Germany, Verde Malaquita concentr, Fabricacion Alemana, Verte Malachite concentre, Verde Malachite concentr. Verde Malachita concentr. 53054, E. Merck Darmstadt” and “Malakiittivihreä”

Chemical:Gray, small crystals.Quantity: about 10 ml

Container:Dark brown glass container with dark red plastic screw top. Dimensions: height: 12 cm, diameter: 5,5 cm

11. a. ”10 gr Fuchsin 22015 S Mikroscop. Farbstoff Ciba”

b. ”10 gr Fuchsin 22015 S Mikroscop. Farbstoff Ciba”

a. Chemical:Dark red-greyish powder.Quantity: about 5 ml.Container:Dark brown glass bottle with dark brown plastic screw top.

Dimensions: height: 8 cm, diameter: 3 cm

b. Chemical:Dark red-greyish powder.Quantity: about 5 ml.Container:Dark brown glass bottle with dark brown plastic screw top.

Dimensions: height: 8 cm, diameter: 3 cm

12. ”Yliopiston Apteekki tetrabromphenolsulfophtalein. 5,0”

Chemical:White powderQuantity: about 10 ml

Container:

50

Dark brown glass bottle with black plastic screw top. On the top text:”E. Merck. Darmstadt”. Dimensions: height: 5 cm, diameter: 2,5 cm

13. ”Korppi Apteekki, Helsinki Neilikkaöljyä Nejlikolja Apoteket Korpen, Helsingfors”

Chemical:Dark brown thick, fragrant liquid.Quantity: about 20 ml

Container:Dark brown glass bottle with black plastic screw top. Dimensions: height: 5,5 cm, diameter: 3 cm

14. a. Two labels: ”Tampereen Rohdos Oy Tammerfors Drog AB Helsinki – Helsingfors, 500,0 jodum, Anal. No 60081 Ph. Nord..” and ”Korppi apteekki Helsinki Etelä-Esplanaadi 2 Puh 628183, Jodikiteitä, Apoteket Korpen, Helsingfors, Södra Esplanaden 2 Tel. 628 183”.

b. Two labels: ”Korppi Apteekki Helsinki 13 Eteläinen Esplanaadikatu 2 Puh. 628 183 Jodikiteitä Apoteket korpen Helsingfors 13, Södra Esplanadgatan 2 Tel 628 183” and ”ulkoisesti nauttiminen vaarallista utvärtes farligt att förtära”.

c. ”Jodikiteitä”

a. Chemical:Grey hard crystals.Quantity: about 100 ml

Container:Dark brown glass bottle with black plastic screw top. On the top text:”E. Merck. Darmstad”.Dimensions: height: 14 cm, diameter: 6 cm

b. Chemical:Hard grey crystals.Quantity: about 100 ml

Container:Dark brown glass bottle with glass top. Dimensions: height: 19 cm, diameter: 8 cm

c. Chemical:Hard grey crystals.Quantity: about 100 ml

Container:Glass bottle with glass top.

51

Dimensions: height: 17,5 cm, diameter: 8 cm

15. ”Kauppatorin Apteekki Apoteket Vid salutorget Helsingissä Helsingfors 17/II-40 Jodicalcium liuos. (1,0 Jod.-2,0 Jod. kal.-97 ccm.) =1,0 Sol.calc. chloride.cntr.-4,0 175.0 M.ds)”

Chemical:Dark brown liquid.Quantity: about 50 ml

Container:Dark brown glass bottle with natural cork top. Dimensions: 16 cm x 6 cm x 3 cm

16. ”Erottajan Apteekki Apoteket vid Skillnaden Helsinki, H:fors, Siansappi viinan2

Chemical:Brown thick liquid. In the bottle are fragments of broken natural cork.Quantity: about 5 ml

Container:Glass bottle with natural cork top. Dimensions: 11 cm x 4,5 cm x 2 cm

Table 5. Chemicals from field laboratory bag A.

Nr. Name Description1 Unknown Chemical:

Dark brown liquid. Quantity: about 20 mlContainer:Glass bottle with white metal screw top. On the bottle is a paper label with text”Vaasan Keskusapteekki puh. 2101, 4099, Tisl. vettä Dest. vatten Ph. F. VI, Centralapoteket i Vasa tel 2101, 4099”.The bottle is an old Alko bottle with remnants of the old product label.Dimensions: height: 23,5 cm, diameter: 7 cm

2 Unknown, on the label written name “reagenssi”

Chemical:Dark brown liquid. On the bottom of the bottle there are white crystals.Quantity: about 50 mlContainer:

52

Glass bottle with grey rubber top. On the bottle is a blue plastic label with text: ”REAGENSSI”.Dimensions: height: 18 cm, diameter: 8 cm

3 Unknown Chemical:Dark brown liquid. On the bottom of the bottle are white crystals. Strong smell of gasoline.Quantity: about 50 mlContainer:Brown glass bottle with glass top. Dimensions: height: 16,5 cm, diameter: 6 cm

4 Unknown Chemical:Dark brown liquid. Strong smell of gasoline.Quantity: about 500 mlContainer:Glass bottle with white metal screw top. The bottle is an old “Alko” bottle with remnants of the old product label still exist. The text on the old product-label is: ”Product of Finland Dry Vodka unflavoured 45° Produced and bottled by Oy Alko Ab Helsinki Finland 015 Distilled from grain”Dimensions: height: 23 cm, diameter: 6,5 cm

5 Unknown on the label written name “jääetikka”

Chemical:Dark brown liquid. Quantity: about 200 mlContainer:Glass bottle with black rubber top. On the bottle is a blue plastic label with text ”JÄÄETIKKA”.Dimensions: height: 18,5 cm, diameter: 8 cm

53

Table 6. Chemicals from field laboratory bag B.

Nr. Name Description1. Acetic Acid, “Etikkahappo” Chemical:

Transparent liquid with strong acetic smell. Quantity: about 500 mlContainer:Brown glass bottle with black plastic screw top. On the bottle is a paper label with text: ”Etikkahappo väk. yli 90%…” .Dimensions: height: 19,5 cm, diameter: 7 cm

2. Unknown Chemical:Dark brown liquid with acetic smell. The liquid contain long, white crystals.Quantity: about 200 mlContainer:Glass bottle with grey rubber top. On the bottle is a paper label with text: ”Valmis sekoitus 20.07.87”.Dimensions: height: 19 cm, diameter: 8 cm

3. “Aniline” Chemical:Dark brown liquid. Quantity: about 20 mlContainer:Brown glass bottle with white plastic screw top. On the bottle are two paper labels with text: ”pro analysi art 1261 Anilin zur analyse C6H5NH2 MERCK …” and “Myrkkyä …. GIFT Livsfarligt att förtära”.Dimensions: height: 15 cm, diameter: 6,5 cm

4. “Aniline” Chemical:Dark brown liquid. Quantity: about 400 ml

54

Container:Brown glass bottle with white plastic screw top. On the bottle is a paper label with text:”pro analysi art 1261 Anilin zur analyse C6H5NH2 MERCK …” Dimensions: height: 15 cm, diameter: 6,5 cm

5. Acetic Acid, “Etikkahappo 1987” Chemical:Transparent liquid with strong acetic smell. Quantity: about 500 mlContainer:Brown glass bottle with black plastic screw top. On the bottle are two paper labels with text: ”Etikkahappo väk. yli 90%…” and ”Hankittu 17.7.87”.Dimensions: height: 19,5 cm, diameter: 7 cm

6. Unknown Chemical:Dark brown liquid with acetic smellQuantity: about 200 mlContainer:Glass bottle with black rubber top. On the bottle is a paper label with text: ”JÄÄETIKKAA”Dimensions: height: 18 cm, diameter: 8 cm

7. “Aniline” Chemical:Dark brown liquid. Quantity: about 400 mlContainer:Brown glass bottle with white plastic screw top. On the bottle is a paper label with text:”pro analysi art 1261 Anilin zur analyse C6H5NH2 MERCK …” Dimensions: height: 15 cm, diameter: 6,5 cm

8. “Aniline” Chemical:Dark brown liquid.

55

Quantity: about 400 mlContainer:Brown glass bottle with white plastic screw top. On the bottle is a paper label with text: ”pro analysi art 1261 Anilin zur analyse C6H5NH2 MERCK …” Dimensions: height: 15 cm, diameter: 6,5 cm

In the field laboratory bag there were also six test tubes. Two of them contained about

20 ml of dark liquid that smellet like fuel oil or diesel. The laboratory tubes were

closed with grey rubber stoppers. The content of both tubes were analysed by FTIR-

spectrophotometer.

3.4.2. FTIR spectroscopy

The interpretation of infrared spectra involves the correlation of absorption bands in

the spectrum of an unknown compound with the known absorption frequencies for

types of bonds. Intensity, shape, and position in the spectrum are significant for the

identification of the source of an absorption band. The method of running the

spectrum can affect the results and sometimes comparisons can be very difficult.

Very small samples of all chemicals from the collection of the Police Museum were

run by FTIR-spectrophotometer Perkin Elmer Spectrum 100 using ATR micro-analyse

method.

Attenuated total reflection infrared (ATR-IR) spectroscopy is used for analysis of the

surface of materials. For most materials, no sample preparation is required for ATR

analysis.

For attenuated total reflection infrared spectroscopy, infrared radiation is passed

through an infrared transmitting crystal with a high refractive index, allowing the

radiation to reflect within the ATR element several times.

56

IR-spectra received were compared to existing IR spectra in IR libraries available on

the Internet and in the literature. (http://www.irug.org, 2007 and

www.webbook.nist.gov/chemistry, 2007). In the interpretation of IR-spectra Table of

Characteristic IR Absorptions was used as well. (http://orgchem.colorado.edu/). The

Table is presented in Appendix4.

IR spectra of chemicals from the Police Museum and their comparison to the known

spectra are presented in Appendix 3.

Comparisons of the chemicals received by the Police Museum from the Technical

Department of Helsinki Police are presented in Appendix 3. IR spectra from IR

spectra libraries are presented on a different scale than the spectra run from the

museum’s collection in the EVTEK Design Institute Laboratory and their comparison

can be difficult. Identification was done by comparing places of characteristic peaks

and their shape.

Below are the IR spectra of the unknown substances from the field laboratory bags

and their analysis. The IR spectrum of the mysterious substance named “siansappi

viinan” is also presented.

Field laboratory bag 1

1. Unknown sample 1

57

Figure 7. IR spectrum of acetic acid.

Figure 6. IR spectrum of unknown sample 1 from laboratory bag 1.

58

The brown colour of the sample suggests that it may contain aniline. The very low pH

(pH measurement results are presented in Table 5 in Chapter 2.4.9.2) and peaks

characteristic for the carbonyl group suggests that most probably the sample is a

mixture of acetic acid and aniline. Mixture is a readymade reagent for testing diesel oil

for the presence of fuel oil.

2. Unknown sample 2

Figure 8. IR spectrum of aniline.

59

Figure 9. IR spectrum of unknown sample 2 from laboratory bag 1.

The dark brown liquid with very low pH and similar IR spectrum to that of sample 1

suggests that the chemical in question is a mixture of acetic acid and aniline. It is a

readymade reagent for testing diesel oil.

3. Unknown sample 3

60

Figure 11. IR spectrum of petroleum according to http://search.be.acros.com/

(accessed 2.1.2008).

Figure 10. IR spectrum of unknown sample 3, from laboratory bag 1.

61

The unknown brown liquid with a strong smell of gasoline is probably a petroleum

sample taken from a tested car. The presence of a small peak characteristic for the

carbonyl group and low pH suggests that the sample is contaminated with acetic acid

or readymade testing reagent.

4. Unknown sample 4

The simple IR spectrum is characteristic of the alkenes group, the almost neutral pH

and strong gasoline smell of dark brown liquid sample suggest that it is a sample of

Diesel oil taken from the suspected car.

Figure 12. IR spectrum of unknown sample 4, from laboratory bag 1.

62

Unknown sample 5

Figure 13. IR spectrum of unknown sample 5, from laboratory bag 1.

Figure 14. IR spectrum of acetic acid from http://search.be.acros.com/, (accessed

2.1.2008).

63

The unknown chemical number 5 from the field laboratory bag contains acetic acid.

The dark brown colour probably comes from slight contamination by aniline. The

aniline content is probably so small that the characteristic peaks are covered by the

acetic acid spectra.

Field laboratory bag 2

1. Unknown sample 1

Figure 15. IR spectrum of unknown sample 1, from laboratory bag 2.

Based on the IR spectrum, pH and strong acetic acid smell we can confirm that the

bottle contains acetic acid.

64

2. Unknown sample 2

Figure 16. IR spectrum of unknown sample 2, from laboratory bag 2.

The dark brown liquid with very low pH and similar IR spectrum as that of samples 1

and 2 from laboratory bag 1 suggests that the chemical in question is a mixture of

acetic acid and aniline. It is a readymade reagent for testing diesel oil. The white

crystals in the sample are a result of a reaction taking place between these two

chemicals. According to p.c. Lappalainen, the reagent could be used for only a short

time (about one week) and after that it no longer worked and white crystals

sedimented in the container. (Lappalainen 2007).

65

3. Unknown sample 3

Figure 17. IR spectrum of unknown sample 3, from laboratory bag 2.

4. Unknown sample 4

Figure 18. IR spectrum of unknown sample 4, from laboratory bag 2.

66

The IR spectra of samples 3 and 4 from field laboratory bag 2 are similar and they

correspond to known IR spectrum of aniline.

Figure 19. IR spectrum of aniline from http://webbook.nist.gov/chemistry, (accessed

3.1.2008).

5. Unknown sample 5

Figure 20. IR spectrum of unknown sample 5, from laboratory bag 2.

67

Given the IR spectrum, pH and smell, we can conclude that chemical 5 from

laboratory bag 2 is an acetic acid.

6. Unknown sample 6

Figure 21. IR spectrum of unknown sample 6, from laboratory bag 2.

The IR spectrum of chemical 6 from laboratory bag 2 is very similar to the IR spectra

of readymade reagent for testing diesel oil (Figure 1, 4 and 11). It contains acetic acid

and aniline.

7. Unknown sample 7

68

Figure 22. IR spectrum of unknown sample 7, from laboratory bag 2.

8. Unknown sample 8

Figure 23. IR spectrum of unknown sample 8, from laboratory bag 2.

69

Based on the IR spectra, chemicals 7 and 8 from the field laboratory bag can be

identified as aniline.

Mysterious chemical named “siansappi viinan”.

The most intriguing of the chemicals from the Police Museum collection is a bottle

containing dark brown, thick liquid with a label “Siansappi viinan” that can be

translated from Finnish as “Pig’s bile in ethanol”.

For analysing the sample I had at my disposal only IR spectrophotometer and pH-

meter. Analysis of IR spectrum was done using a Table of Characteristic IR

Absorptions (Appendix 4). Characteristic peaks found in the IR spectrum are

presented in Table 7.

Figure 24. IR spectrum of “Siansappi viinan”

70

Table 7. Characteristic IR absorption for chemical named “Siansappi viinan”.

Frequency, cm-1 Bond Functional group

3500 - 3200 OH, stretch alcohols, phenols

3000 - 2850 CH, stretch alkanes

1600 -1585 CC, stretch aromatics

1470 -1450

1370 - 1350

CH, bend

CH, rock

alkanes

1250 - 1020 CN, stretch aliphatic amines (?)

900 - 675 CH aromatics

The IR analysis cannot answer the question what is in the bottle with the curious

name nor where it was used. Most probably the bottle contains a mixture of alcohol,

amines and possible some fats.

3.4.3. pH measurement

For additional technical information, pH of samples of chemicals taken from the field

laboratory bags were measured using Wissenschaftlich-Technische-Werstättem pH

330, electrode SenTex 41. Only chemicals from the laboratory bags were measured

because most of them were unknown, and based on the IR-spectra, they were

mixtures of two organic compounds: aniline and acetic acid. Information on the pH of

chemicals confirmed the presence or absence of acetic acid.

The pH of other chemicals received from the Technical Department of the Police in

Helsinki was not necessary because their identification was complete for all except

one (siansappi viinan). Tables 8 and 9 present results of pH measurements.

Table 8. pH of chemicals from field laboratory bag A.

Sample pH1. Unknown 2,02. Unknown, on the label “reagenssi” 2,38

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3. Unknown 2,224. Unknown 6,55. Unknown on the label “jääetikka” 1,88

Table 9. pH of chemicals from field laboratory bag B.

Sample pH1. Acetic Acid, “Etikkahappo” 1,022. Unknown 2,103. Aniline 6,774. Aniline 6,875. Acetic Acid, “Etikkahappo 1987” 0,896. Unknown 0,977. Aniline 7,778. Aniline 7,34

3.4.4. X-Ray Fluorescence Spectroscopy

A well-established method of quantitative element analysis is non-destructive X-ray

fluorescence method XRF. The method was used to analyse elements in solid

chemicals received from the Technical Department of the Police in Helsinki. The X-

ray fluorescence analysis confirmed the presence of elements in the chemicals

studied and complemented the analysis by IR spectrometry. Table 10 presents

results of the X-ray fluorescence of chemicals. The chemicals present in the collection

in more than one sample were not measured because their IR spectra analysis

confirmed their identification.

Table 10 presents the X-ray fluorescence analysis of the solid chemicals from the

Police Museum collection. The method of analysis is very sensitive and can detect

parts-per-million (ppm), for this reason the results reveal unexpected elements.

Those elements are most probably contamination of the sample.

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Table 10. Results of X-ray fluorescence analysis for solid chemicals from the Police

Museum.

Sample Elements detected by XRF1. Anthracene K 848

Mn 153Fe 341

2. Zinc Silicate Ca 3101K 13500S >10 %P >10 %Ba 6030Cr 665Mn 762Fe 1117Zn >10 %Pb 225Sr 332Mo 753

3. Silver Nitrate Ag 46434J 222K 79458S 16108P 49105Cr 55Mn 109Fe 109Ni 415Cu 75Pb 40Sr 19Zr 48Mo 122Sn 4355

4. 1-Naphtylamine-4sulphonic Acid

S 27212Cr 37Mn 86Fe 110

10.Malachite-Green K 392Cr 38Mn 72

73

Fe 979Cu 575

11.a. Fuchsine K 816Cl 31265Cr 47Mn 93Fe 1156

14. c. Iodine J 14076Ba 330Mn 133Fe 203Ni 598

3.4.5. Smell

One of the chemical properties that can be useful, but not always trustworthy, for

identification of chemical substances is their smell. The characteristic, recognizable

smell of vinegar, gasoline or ethanol can indicate the presence of those substances

or their derivatives. However, when sniffing the sample we have to be very careful so

as not to expose ourselves to a dangerous or unpleasant experience. The best way

is to do it in a ventilation hut or well ventilated space while waving delicately over the

open chemical container so that only a very small amount of vapors reaches the

nose. We should never try to smell chemicals that are labelled with warning signs

(danger, poison, explosive etc.)

The characteristic smell for some chemicals was useful in recognizing substances

from the Police Museum collection, especially unknown, unlabelled chemicals from

the field laboratory bags. Two kind chemicals were identified in these bags – acetic

acid and aniline. They were ingredients of a reagent used for testing diesel oil that

was prepared just before the police patrols went into action or possibly even in the

field. Police officers used any available containers and often forgot to label them. For

this reason there were several bottles with unknown substances. Some of the bottles

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were labelled acetic acid even though the liquid was dark brown. Some had a

vinegary smell while others, similar in colour, did not. In some samples a strong

gasoline smell could be recognized. Smell indicated the presence of chemicals that

otherwise might not be expected. Smell observations (Table 3 and 4) were confirmed

by IR spectrographic analysis.

3.4.6. Interpretation of research results

IR spectrography confirmed the presence of the chemicals named on the container’s

label or suspected. For unknown substances from the field bags, IR spectrography

and pH measurement were enough to identify the chemical.

Interpretating of the X-Ray Fluorescence results was sometimes difficult especially for

zinc silicate and silver nitrate where many elements could be recognized. This could

probably be explained by sample contamination. The same explanation comes to

mind when looking at results for Fuchsine or Malachite Green, whose chemical

formulas do not explain the presence of so many elements.

The one chemical that should be further tested is “siansappi viinan”. The chemical is

organic and gas chromatography analysis would reveal its contents.

3.5. Active and preventive conservation of chemicals from the Police Museum in

Tampere

For chemicals from the Police Museum collection both active and preventive

conservation was executed. The active conservation was applied only to the

chemicals’ containers. In active conservation two steps were taken. One was

conserving the containers of the chemicals and their labels. This conservation was

mainly done by gently cleaning the glass containers. At first dust was removed using

a microfibre cloth and then the containers’ surfaces were wiped with cotton wool and

ethanol. Paper labels were cleaned with chemical rubber cleaner - soft Wishab

sponge (Lascaux). Paper labels that were damaged were supported with thin

Japanese paper using wheat starch glue.

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Active conservation can include taking samples of all chemicals present in the

collection and their identification by instrumental methods.

Preventive conservation was done for all chemicals based on the results of

identification analysis and literature. Very helpful in preventive conservation were

material safety data sheets (MSDS). Material safety data sheets are made for most

chemical substances. They contain data regarding the chemical and physical

properties of the substance. They also provide information on procedures for safe

handling and storage. Toxicity, reactivity, health effects and other information about

possible hazards are provided as well.

Material safety data sheets are made specifically for chemicals that are produced and

commonly used in nowadays. For mixtures of chemicals and for older chemicals there

may not be a material safety data sheet. The aging process of chemicals and

possible changes in the chemicals should also be taken into consideration when

using MSDS.

The chemicals from the Police Museum collection are relatively new (about 70 years

old) and for all of them except mixtures MSDS could be found. Based on the

information from material safety data sheet decisions about storage or disposal of

chemicals were made.

3.6. Literature research of chemical and physical behaviours of chemicals the from

Police Museum

Most information about the behaviour of the chemicals from the Police Museum

collection was obtained from the material safety data sheets. In the conservation

report, the MSDS for all stored, pure chemicals were included. Other information

about possible reactions between chemicals that may occur in extreme conditions in

a museum, when chemical containers are broken or chemicals spill could be studied

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on an interesting website provided by the U.S. Department of Energy

(http://www.hss.doe.gov/healthsafety/wshp/chem_safety/, viewed 6.1.2008).

3.7. Decision-making

When the chemicals in a collection are identified and their chemical and physical

properties are known, then the most difficult and responsible process of decision

making starts.

Part one of this study discussed why the chemicals in museum collections should be

conserved and preserved. They are historical evidence of our past that should be

studied and preserved. They are the real things from the past that museum visitors

come to see.

For these reasons chemicals and not only their containers should be preserved

whenever possible.

In making decisions about preserving chemicals in museum collections many aspects

should be taken into consideration. The prime concern should always be the safety of

people, museum staff and visitors. For these reasons, chemicals that can explode,

burn, release dangerous vapors or are toxic should not be stored or exposed in

museums. Preservation in museum facilities of chemicals that are acidic, corrosive,

reactive or hazardous in other ways to people and other museum objects is

questionable. Only separate storage rooms and qualified staff should take care of

storing these types of chemicals. Exhibiting them would be very difficult and many

safety procedures would have to be undertaken.

Many hazardous chemicals like acids or solvents are well known and easy to find on

the market. Their production is well documented and therefore their historical value is

not high. However, they pose a high risk to museum staff, visitors and to other

artefacts in the museum collection. In this situation it is better to remove such

chemicals from the collection. Their containers, however, can be preserved after their

content has been removed.

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Chemicals that are unknown and unlabelled should also be disposed for safety

reasons. If an unknown chemical is unique or is historically important, further

investigation and research should be done to analyse and describe the artefact.

The chemicals that have been identified and whose chemical and physical properties

are known and reactivity predictable, preventive conservation should be performed.

They have to be stored or exhibited under correct conditions in which they are most

stable.

Taking into consideration all the above aspects of storing and exhibiting chemicals,

decisions concerning the preservation of chemicals from the Police Museum were

made.

The biggest problems were with the chemicals from the field laboratory bags. There

were only two chemicals: aniline, acetic acid and their mixtures, some of them were

not labeled. Samples of gasoline were found in the bags as well. The chemicals from

the field laboratory bags are listed in Tables 3 and 4. Both chemicals are hazardous

and both are typical laboratory chemicals that are commonly produced and used.

They were carried in the laboratory bags together with other artifacts used for testing

diesel oil by the traffic police. Storing those hazardous chemicals, one of which is a

concentrated organic acid and other is a poison, jeopardizes other artefacts in the

bags and indeed the bags themselves. Those two arguments prevailed in the

decision-making and acetic acid, aniline and their mixtures were disposed of.

Samples that contained gasoline were disposed of as well for the same safety

reasons.

The field laboratory bags will be on show in the permanent exhibition in the Police

Museum. It is possible that for aesthetic and educational reasons neutral liquids with

similar colours will be placed in the containers.

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In Table 2 are chemicals that were obtained by the Police Museum from Helsinki

Technical Department of Police. Most of the chemicals are not dangerous. However,

four of them were disposed of: anthracene, acetone, iodine and iodine solution.

Anthracene’s toxic properties have not been fully investigated, but it is known that

anthracene is very dangerous to the environment. It can also cause irritation to skin

and eyes. The amount of anthracene in the Police Museum collection was quite large

(about 0,5 kg) and for this reason deaccession was decided on.

Acetone was removed from the museum collection due to its flammability.

Iodine is toxic to people and hazardous to the environment. It has the ability to

sublimate and colour surfaces dark brown. For these reasons and also because it is a

common laboratory chemical iodine was removed from the collection. For these same

reasons iodine solution was disposed of.

3.7.1. Disposal

The Police Museum does not have chemicals in their collecting plans and for this

reason and the reasons presented in Chapter 2.9.6. some of the chemicals were

disposed of. Chemicals on which a decision about disposal was made were carefully

removed from their containers and placed into other disposable glass containers that

were labelled. The chemicals’ containers were cleaned of all residues of the

chemicals with appropriate solvents and after that washed with water and Mini Risk

soap, rinsed and dried. The solvents used for washing the containers and soap-water

were gathered in labelled bottles as well.

All chemicals and solvents used for rinsing and washing containers were taken to

hazardous waste facilities – Ekokem Oy Ab, Riihimäki.

3.7.2. Storage

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The chemicals that were not considered dangerous or hazardous at normal

temperature and pressure were placed in storage. For storing chemicals two

polypropylene boxes with tight lids were prepared. On the bottom of the boxes is a

plate made of 5 cm thick polyethylene foam – Ethafoam (Dow Chemical Company)

where openings in the shape of stored chemicals’ containers were cut. The chemicals

in their original containers were placed in the tightly cut openings. The boxes with

chemicals are stored separately from other museum artefacts in a dark air-

conditioned storeroom at 18°C.

Photo 8. Chemicals from the Police

Museum in Tampere packed for

storage using Ethafoam to keep the

bottles safely in place.

Photo 9. Chemicals from the Police Museum in Tampere packed for storage.

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4. How to preserve chemicals in museum collections

This section of the thesis describes guidelines for the conservation and preservation

of chemical substances. The author of the thesis acknowledges that specific rules

regarding the conservation of chemicals are impossible to list in this document due to

the wide variety of substances.

In his work, “Contemporary Theory of Conservation”, Vinas describes a revolution of

common sense in conservation. He calls for gentle decisions and sensible actions.

(Vinas, 2005 pp 212 - 214).

Similar attitudes are crucial especially in the conservation of chemical collections.

4.1. Preventive conservation of chemical substances in a museum

There is extensive information available regarding the hazards of chemical

substances and about safety precautions, but relatively little information about their

conservation and maintenance. In most cases conservation of chemicals in museum

collections will be limited to preventive conservation only.

According to the American Institute for the Conservation of Historic and Artistic

Works, preventive conservation is the mitigation of deterioration and damage to

cultural property through the formulation and implementation of policies and

procedures for the following: appropriate environmental conditions; handling and

maintenance procedures for storage, exhibition, packing, transport, and use;

integrated pest management; emergency preparedness and response.

Preventive conservation is an ongoing process that continues throughout the life of

cultural property, and does not end with interventive treatment. Preventive

conservation is not only cheaper in the long term but also ethically preferable.

The preventive approach is particularly appropriate for collections that contain

chemical substances, because the introduction of treatment that entails using some

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other materials such as water, adhesives, consolidants etc., could possibly

compromise an artefact’s research potential.

The conservation of chemical substances is mostly limited to preventive conservation

because of the technical limitations. The aim is to slow down the aging process and

deterioration of chemicals as well as to provide them with a safe environment in which

their chemical content and physical properties will not change. The preventive

conservation of chemicals should also be reviewed with regard to other artefacts in

the museum collection. Safely stored and exhibited chemicals will not pose a danger

to other artefacts in the collection. The primary duty of a museum in which there is a

collection of chemical substances is to care for the safety of the staff and the public.

Effective policies and procedures must be developed and implemented to ensure the

safety of people.

4.2. Standards for collecting and preserving chemicals

Every museum should have written standards for collecting and preserving objects.

Those standards should explain why the museum collects particular groups of

artefacts and guide museum staff in their work. It will also help in making decisions as

to whether to include some object in the museum collection.

The collecting of chemicals needs special standards and guidance for the museum

staff and should be carefully considered because of the danger that some chemicals

can cause to people and the rest of the museum collection. Chemicals in the museum

may be a part of the large collection that concerns a part of our history, like, for

example, police museums or medicine museums. Chemicals may also be the only

objects in the collection as, for example, in pharmacy museums.

4.2.1. Legal possession of chemicals

A museum should not only be legally entitled to store chemicals but also possess all

the required licenses and permits. The legality of some chemicals may vary between

82

countries. Chemicals for whose possession special permission is required are not

only illegal drugs, dangerous poisons or radioactive materials, but can also be pure

ethanol (98%). For example, in Finland permission from the Social and Health Care

Product Control Centre (Sosiaali- ja terveydenhuollon tuotevalvontakeskus) is

required for the possession and use of strong, not denatured ethanol.

4.2.2. Safety of the museum

Museums can collect only chemical substances that they have the facilities and

expertise to care for. If the museum does not have appropriately qualified and

experienced staff it should not hold artefacts that contain dangerous or in other ways

critical chemical substances, but transfer them to a museum that has specialized

facilities and qualified staff. In cases where this is not possible, the museum should

consider disposing of critical chemicals for safety reasons. When human life or health

is in question the priorities are clear.

Chemicals that are considered safe for human life may harm other artefacts in the

collection and their storage and possible exhibition must be carefully planned.

Evaporation and spilling of chemicals and the consequences of this should be taken

into consideration when planning the storage and exhibition of chemical substances.

There may be unstable substances in museums that are not dangerous and can be

safely stored. A good example of this kind of chemical is sugar. Sugar hydrolyzes

very easily, converting sucrose into syrup of fructose and glucose and changing

colour. Unstable chemicals should be stored in proper environments and checked

frequently to prevent damage. Expert attention should be paid to any chemical

problems occurring during the storage or exhibition of chemical substances. Any

conservation treatment, whether active or preventive, should be discussed with

professionals and well documented.

Chemical substances in museums may hold interest for researchers and therefore

there should be an option for non-destructive research on chemicals after getting

approval from the museum curator. (Paine. 1992, pp.13-23).

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4.2.2.1. Health and Safety Policy concerning collection of chemicals

Museums with collections of chemicals should make clear and well-known policies

concerning the health and safety of the personnel and visitors. This document should

provide common sense guidance for carrying out museum work on the chemical

collection. The document should minimize any risk to the health and safety of the

museum’s staff and ensure that objects are stored, handled, and transported safely.

The document should contain the following information:

1. First Aid

The information and contact information of the person in the museum who has

qualifications to give first aid if required.

2. Policy about working alone

When working alone other colleagues from the museum should know where

you are and how long your work will take. A person who works alone should

not take any risky actions or do work that requires more than one person.

3. Use of equipment and tools

No equipment or tools should be used without training.

4. General guidelines for museum staff

- No food during work

- Careful and gentle handling of objects using both hands

- Use gloves and, if necessary, protective clothing when handling chemical

substances.

- Chemicals from the collection can be handled and conserved only in

specialized facilities with good ventilation.

- Moving the chemical substances from one place to another should be well

planned. The weight of the object, its size, hazardous notes and storage

recommendations should be checked.

- Exposure to any harmful chemical substances should be minimized. The

chemicals must not be open unless necessary, especially if unlabelled. Do not

touch your eyes or mouth after handling chemical substances and always

wash your hands carefully after work.

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- Chemicals should be packed safely with appropriate padding, so they will not

spill and their containers will not break.

- If you feel unwell and suspect that it is because of physical contact with a

chemical substance, seek medical advice immediately.

- Never dispose of chemical substances by washing them down the sink or

putting them into the garbage.

This draft of the Health and Safety Policy for collections of chemicals was made

based on the policy used in the Museum of the Royal Pharmaceutical Society in

London. (Hudson 2005).

This is only a draft that can be a basis for local policymaking where the needs and

problems of the particular collection are considered.

4.2.3. Disposal of chemical substances

Disposal is the permanent removal of the artefact, or part of it, from the museum’s

collection by any means. It may be sold, exchanged or donated to another museum. It

can also be destroyed. Disposal of the artefact is the most radical and final step that a

museum can take. The disposal from the collection of chemical substances that may

be poisonous or hazardous should be done with a conservator and the authorities of

the Regional Solid Waste Management present (Ongelmajätehuolto). Before making

the decision, a full assessment of the artefact should be made. If the chemical is of

unknown origin, the museum should consider the possibility that other information

about the chemical may become available later.

For chemical substances, often only the chemical and not its container are disposed

off. This procedure often requires special facilities and special safety procedures

because of the possible danger posed by the removed chemical. (Paine 1992, pp 13 -

23).

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4.3. Advice on the preservation of chemicals

In the chapters above, it was mentioned that a museum is not the best place to

preserve unknown, unstable or hazardous chemicals because it does not have

specialized facilities and schooled professionals. Only carefully bottled chemicals that

are well sealed to prevent possible reactions with oxygen and moisture are safe to

store in the museum. Stable chemicals, if carefully stored, can be preserved for many

years. According to Lin of the MDPI Samples Preservation and Exchange Project,

many pharmaceutical companies have properly archived organic samples that were

prepared more than fifty years ago but still are usable and can be used for their

primary purpose. (Lin, 2005).

It is certain that stable chemicals, particularly organic compounds, can be stored at

room temperature without undergoing any chemical changes.

4.3.1. Active conservation of chemicals

Active conservation of chemicals is mostly limited to cleaning the container.

Sometimes, if we know the chemical’s properties and we have the facilities to do it,

the cleaning of the chemical itself is possible. If the chemical contains visible

impurities like pieces of cork floating in the liquid, removing them can be done by

filtration. Some impurities may catalyse chemical reactions and if possible it is better

to remove them from the chemical.

Restoration is often part of the conservator’s work and is done for aesthetic or

educational reasons, especially for artefacts that are exhibited. Chemicals that had to

be removed from their containers and disposed of due to hazardous nature can be

restored by placing a neutral substance reminiscent the original one in the container.

If the conservation of furniture with a broken leg required reconstruction of that leg to

make the furniture more aesthetic and informative, then placing a replica of the

dangerous chemical substance plays the same role. This should be mentioned in the

description of the object.

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4.3.2. Preventive conservation of chemicals

One of the first steps in planning preventive conservation for the collection of

chemicals is survey of the collection and long-term monitoring. In the preventive

conservation of chemicals we have to consider all factors that can affect chemicals

during their storage or possible exhibition. As for other artefacts in the museum

collection, the four most important factors can affect chemicals: temperature, light,

moisture and oxygen. Control of temperature and moisture is costly but possible with

air-conditioning systems. Oxygen sensitive chemicals should be stored with oxygen

absorbers. One of the most used in museum collections is Ageless® oxygen

scavenger (Mitsubishi). (Day 2005, pp.426-433)

Safe containers for chemicals provide good protection against other environmental

factors like inner pollutants. They can also restrict the vapor of the chemical that

otherwise would become an inner pollutant for the rest of the collection. For example,

carboxylic acid emissions from cabinets and other storage materials can result in

alteration of the salts of weak acids like borates or carbonates. Carboxylic acid

emission can also increase the corrosion of non-noble metallic salts. Other metals like

silver, copper and mercury are sensitive to reduced sulphur gases. Vapors of mercury

that can often be found in museum collection as a part of chemical collection or part

of the different types measuring instruments are particularly dangerous. It is not only

dangerous to people, but also to metals. All metallic elements except iron are capable

of forming amalgams with mercury. (Waller 1999, pp.113–18).

The criteria for good a chemical container are: stable materials and effective closure.

Most of the chemicals come to the museum collection in various glass containers.

Glass is very stable for most chemicals. For a chemical sensitive to light, tinted glass

containers should be used or such a of chemical should be placed in other containers

that can provide light protection.

87

According to Kontradas of theNational Museum of American History, older, cork-top

or glass-top containers are often more secure and stable than new ones from the

1960s or 1970s. (Kondratas 1991, pp 55 – 62).

Below we describe the properties of some containers most often used for chemicals.

4.3.2.1. Screw-top containers

The tops of the containers can be made of different materials and their stability may

vary. They can be made of metal or plastic.

The best sealing properties have screw tops made of polypropylene with polyethylene

inner liner (Photo 10). Those polymers (PP and PE) are stable with most chemicals.

Only hot aromatic hydrocarbons or chlorinated hydrocarbon solvents can affect

polypropylene and polyethylene. For the liner polyethylene terephthalate (PET), for

example Melinex®, can also be used. Tops made of polypropylene may sometimes

be discolored over time and under the effect of some chemicals, like for example,

iodine. (Suzumoto 1995, pp. 217- 220).

Photo 10. Chemical from the

Police Museum in Tampere.

Bottle with polypropylene

screw-top.

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4.3.2.2. Ground glass jars

Old chemical jars were often closed with a ground glass top (Photo 11). Such tops

were made of a carefully matched glass stopper with a sealing surface ground to a

fine roughness, mated with a glass vessel with finely ground surface on the

container’s inside neck. Ground glass tops are often not very tight and some kind of

sealing compound like grease or wax must be applied. This may cause contamination

of the stored chemicals. Other problems with ground glass tops are that they often get

stuck so that opening can be very difficult or sometimes impossible.

In containers with ground glass tops liquid chemicals or easily evaporating chemicals

are prone to evaporation of insufficient sealing and can cause damage when spilled.

Solid chemicals can be safely stored in this type of jars if great care is taken not to

contaminate the chemical with a sealing compound. (Clark, 1995, p.221).

Photo 11. Chemical substance

from the Police Museum in

Tampere. Glass container with

ground glass stopper.

89

4.3.2.3 Bail-top containers

Bail-top containers have a gauge wire and cam mechanism to lock down a glass lid

with a rubber gasket. The sealing properties of this type of lid are very good, however

the rubber gasket may be affected by some chemicals, becoming brittle and impairing

the efficiency of the seal. The rubber gaskets should be checked frequently to avoid

leakage or evaporation of chemicals. (Suzumoto 1995, pp. 217- 220).

4.3.2.4. Metal lids

Metal lids or screw tops are usually made of steel and are often plated with brass

inside and painted. All metal lids and tops will eventually corrode, usually rusting from

the inside out. This will occur if the chemical stored in the container contains water,

alcohol, formaldehyde etc. Dust settling on the lid in high humidity makes very good

conditions for external rust to form. Metal lids and tops often have cardboard liner that

can be easily damaged or shrink and cause evaporation or leakage. The metal lid or

top can be tightened by changing the liner to polyethylene film or foam. If this does

not give sufficient tightness because of the lid damage, changing the lid to

polypropylene should be considered. (Suzumoto 1995 pp. 217- 220).

4.3.2.5. Bakelite resin lids

Lids and tops made of bakelite resins are almost always black or dark in colour with a

hard smooth surface. Some chemicals that contain alcohol may embrittle the bakelite.

Photo 12. Bail-top jar.

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Another problem with bakelite is that it has a different expansion-contraction rate from

glass and changes in temperature over time will loosen the lid. This will cause

evaporation or spilling problems. To tighten the bakelite lid inner liner made of

polyethylene foam or polyethylene terephthalate film should be added.

4.3.2.6. Double-container system

Chemicals that are very volatile can be placed in a double-container. The same

system can be used when the chemical’s container is not tight but has historical value

and is not to be deaccessed. The double-container system allows the integrity of the

object to be preserved without removing the chemical to another container and

preserving the object (the chemical and its container) separately.

The double-container system consists of two jars. One, the inner, is the original

chemical’s container that is placed in a larger glass jar. On the bottom of the larger

container polyethylene foam is placed (for example: Ethafoam). In the foam an

opening of the size of the bottom of the chemical’s container is cut. This will ensure

that the chemical’s container is kept in place. If the chemical’s container is large or

Photo 13. Chemical substance

from the Police Museum in

Tampere. Glass container with

bakelite screw-top.

91

heavy, another ring made of polyethylene foam can be placed in the upper part of the

outer container. (Gisbert 1995, pp. 225-226).

The double-container system is recommended for use with all chemicals in the

museum collection. It is the safest way to store them packed in tight stable containers

that can protect museum staff from possible dangerous vapors and artefacts from the

of chemicals stored in the same place. At the same time the chemicals are protected

from environmental factors that can cause damage.

Photos 8 and 9 show a packing system used in the Police Museum in Tampere.

Chemicals after survey, research, and conservation are placed in tightly closed

polypropylene boxes. On the bottom of the boxes is polyethylene foam with openings

where bottles of chemicals are placed. Chemicals packed in this way are stored at

room temperature on a separate shelf in the museum’s store room.

4.4. How chemicals are preserved in museums – a survey

To gather information about the management and conservation of chemicals, an

inquiry was sent to several museums that tend to collect chemical substances. The

inquiry was sent to pharmacy museums, police museums and war museum around

the world. Answers, mostly from the curators, help us see how museums are dealing

with problems that are caused by unusual historical objects in their collections.

The practices are different and very often dictated by practical, physical and financial

constraints.

Figure 25. Double-container system with two supporting rings

of polyethylene foam. (Gisbert 1995, pp. 225-226).

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For police museums, where chemicals are only a small part of the collection,

conservation is often limited to storing the chemicals in a stable environment or

disposing of them. The Netherlands Police Museum has a lot of items related to crime

scene investigation that are sometimes not identified. The museum decided that

tubes filled with fingerprinting ink and powders for fingerprint lifting will be preserved

in their original containers but all other types of chemical fluids will be disposed of.

(Breukers 2006).

The Justice and Police Museum in Sydney also has some chemicals and forensic

samples that are kept in their original glass or plastic containers in dry, dark and cool

storage, wrapped in acid free tissue and bubble-wrap. (Ridley. 2006).

Other police museums, like the Police Museum in Belfast or the New York Police

Museum that only have a few chemicals in their collection preserve them in the same

way as other objects, checking only their toxicity. (Brockner, 2006) and (Forrester,

2006).

Pharmacy and medicine museums have to deal with a large collection of chemical

substances of various origins: plant, mineral, animal and synthetic.

A very large and original collection of chemicals is located at the Niagara Apothecary

Museum that dates from 1820. All chemicals except substances that contain

narcotics are stored in their original containers in the exhibition. The controlled

chemicals or drugs, regardless of potency, were disposed of. The nineteenth century

bottles and jars are placed on the shelves and packages of drugs and chemicals,

mostly unsealed, are stored in bins and drawers below as in their time. For details on

storage and possible conservation of chemicals the museum staff uses the Merck

Index as a reference. The first edition of this appeared in 1889 and publication

continues to the present. (Stieb, 2006).

93

In Albany College of Pharmacy, in the Throop Pharmacy Museum, Material Safety

Data Sheets are used as references for providing a safe environment for chemicals.

(Obos, 2006).

Most pharmacy museums, like for example Deutsches Apotheken-Museum or

Helsinki University museum Arppeanum store their chemicals in the original

containers, providing them with a stable environment. There is concern if something

else should be done to safely preserve their collection of chemicals. (Sinisalo 2006);

(Huwer, 2006).

Below are some chemicals in museum exhibitions. The photos were made in war

museums during the author’s travels in France, 2007.

The different approaches and concerns about chemicals as museum objects can be

seen in these few museums.

Photo 14. Empty chemical bottles in old display cabinets.   Flaubert Museum and

Medical History Museum. Rouen, France.

94

Photo 15. Bottle with an

unknown chemical substance.

Flaubert Museum and Medical

History Museum. Rouen,

France.

Photo 16. Empty medicine

bottles. Flaubert Museum and

Medical History Museum.

Rouen, France.

95

Photo 17. Mercury placed in a glass bottle with a metal screw top. Flaubert Museum

and Medical History Museum. Rouen, France.

Photo 18. Medicine case with

medicines still in place in

original containers. Equipment

of the US Army, WWII.

Airborne Museum at Saint-

Mere-Eglise, France.

96

Photo 19. Capsules of morphine used by US Army medics during WWII. The

capsules are empty. Airborne Museum at Saint-Mere-Eglise, France.

Photo 20. Bottles with chemicals used in a US Army field hospital during WWII. The

chemicals are in their glass containers with damaged rubber tops. Airborne Museum

at Saint-Mere-Eglise, France.

97

Photo 21. Chemicals from a

German field hospital from

WWI, near Verdun. Chemicals

unearthed and placed on

display. Ossuarive de

Douaumont at Verdun, France.

Photo 22. Chemicals from a

German field hospital from

WWI, near Verdun. Chemicals

unearthed and placed on

display. Ossuarive de

Douaumont at Verdun, France.

Photo 23. Chemicals from a

German field hospital from

WWI, near Verdun. Chemicals

unearthed and placed on

display. Ossuarive de

Douaumont at Verdun, France.

98

5. Conclusions

The primary concerns of a conservator should be the preservation and care of

historical objects, whether a painting of renown or bottle of a paraffin from the 1950s.

A museum object’s integrity and condition provides historical information and helps us

interpret our history and culture. It is the conservator’s responsibility to preserve an

object, including chemical substances, in the condition that will convey the most

historical meaning and knowledge for posterity.

Chemicals as museum objects evoke concern and even fear in many museum

professionals and their first reaction is to flush them down the sink or pack them

tightly, place them in storage and forget about them.

Chemicals, however, have a very important role in understanding the chemical and

medical history of our society. Therefore guidelines for responsible preservation and

exhibition chemicals should be created.

The first step, as for other objects in a museum, is identification. The information

about known chemicals can be found in different sources, such as the MSDS

(Material Safety Data Sheet) or the Merck Index. Those sources give information

about chemical and physical properties, possible toxicity and other health concerns,

as well as handling and storage advice. Sometimes information is hard to find if the

chemical substance contains many ingredients, making its toxicity and stability

difficult to predict.

The safest way to preserve and conserve chemicals is always common sense,

especially when dealing with hazardous materials. The primary concern must always

be human well-being and the preservation of dangerous substances is only possible if

the museum has specialized facilities and a qualified staff. Otherwise it is better to

give the critical objects to other museums that have the capability to preserve it. The

last resort is disposal. This has to be done by the Regional Hazardous Waste

99

Management. The decision for disposal should be weighed carefully and the chemical

well documented.

Museums that have a collection of chemicals should make precise safety polices and

guidelines for the storage and handling of chemicals.

Chemicals from the Police Museum were identified and after that a proper storage

solution was devised for them. The Police Museum does not have safe facilities for

storing hazardous and toxic chemicals and for this reason some of the chemicals

were disposed of. The chemicals that were disposed of were chemicals produced in

large quantities today with no special historical value, but their dangerous properties

could have caused problems for the museum staff and posed a danger to other

objects in the collection.

100

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105

Table of FiguresFigure 1. EU standard toxic symbol, as defined by Directive 67/548/EEC.Figure 2. Modes of oxygen uptake versus time (according to Feller 1994).Figure 3. Triple point of three existing phases.Figure 4. Preservation Calculator Figure 5. Electromagnetic spectrum.Figure 6. IR spectrum of unknown sample 1 from laboratory bag 1.Figure 7. IR spectrum of acetic acid.Figure 8. IR spectrum of aniline.Figure 9. IR spectrum of unknown sample 2 from laboratory bag 1.Figure 10. IR spectrum of unknown sample 3, from laboratory bag 1.Figure 11. IR spectrum of petroleum according to http://search.be.acros.com/ (accessed 2.1.2008).Figure 12. IR spectrum of unknown sample 4, from laboratory bag 1.Figure 13. IR spectrum of unknown sample 5, from laboratory bag 1.Figure 14. IR spectrum of acetic acid from http://search.be.acros.com/, (accessed 2.1.2008).Figure 15. IR spectrum of unknown sample 1, from laboratory bag 2.Figure 16. IR spectrum of unknown sample 2, from laboratory bag 2.Figure 17. IR spectrum of unknown sample 3, from laboratory bag 2.Figure 18. IR spectrum of unknown sample 4, from laboratory bag 2.Figure 19. IR spectrum of aniline from http://webbook.nist.gov/chemistry, (accessed 3.1.2008).Figure 20. IR spectrum of unknown sample 5, from laboratory bag 2.Figure 21. IR spectrum of unknown sample 6, from laboratory bag 2.Figure 22. IR spectrum of unknown sample 7, from laboratory bag 2.Figure 23. IR spectrum of unknown sample 8, from laboratory bag 2.Figure 24. IR spectrum of “Siansappi viinan”Figure 25. Double-container system with two supporting rings of polyethylene foam. (Gisbert 1995).

106

Table of Photos

All photos presented in the thesis were taken by Elzbieta Djupsjöbacka

Photo 1. Ossuarive de Douaumont at Verdun, France. Medical equipment from the First World War.Photo. 2. Airborne Museum at Saint-Mere-Eglise, France. Chemicals that were in American parachutists’equipment.Photo 3. Memorial Museum at Caen, France. Medical equipment from a German field hospital. Photo 4. Damaged container with silver nitrate from the collection of Police Museum. Photo 5. Bottle of aniline with damaged lid, from the collection of Police Museum.Photo 6. Field equipment bag of chemicals for testing the purity of gasoline. From the collection of the Police Museum.Photo 7. Test tubes with unknown liquid found in one of the mobile police field bags for testing the purity of gasoline. Police Museum collection.Photo 8. Chemicals from the Police Museum in Tampere packed for storage using Ethafoam for keeping bottles safely in place.Photo 9. Chemicals from the Police Museum in Tampere packed for storage.Photo 10. Chemical from the Police Museum in Tampere. Bottle with polypropylene screw-top.Photo 11. Chemical substance from the Police Museum in Tampere. Glass container with ground glass stopper.Photo 12. Bail-top jar.Photo 13. Chemical substance from the Police Museum in Tampere. Glass container with bakelite screw-top.Photo 14. Empty chemical bottles in old display cabinets.   Flaubert Museum and Medical History Museum. Rouen, France.Photo 15. Bottle with an unknown chemical substance. Flaubert Museum and Medical History Museum. Rouen, France.Photo 16. Empty medicine bottles. Flaubert Museum and Medical History Museum. Rouen, France.Photo 17. Mercury placed in a glass bottle with a metal screw top. Flaubert Museum and Medical History Museum. Rouen, France.Photo 18. Medicine case with medicines still in place in original containers. Equipment of the US Army, WWII. Airborne Museum at Saint-Mere-Eglise, France.Photo 19. Capsules of morphine used by US Army medics during WWII. Capsules are empty. Airborne Museum at Saint-Mere-Eglise, France.Photo 20. Bottles with chemicals used in a US Army field hospital during WWII. The chemicals are in their glass containers with damaged rubber tops. Airborne Museum at Saint-Mere-Eglise, France.Photo 21. Chemicals from a German field hospital from WWI, near Verdun. Chemicals unearthed and placed on display. Ossuarive de Douaumont at Verdun, France.

107

Photo 22. Chemicals from a German field hospital from WWI, near Verdun. Chemicals unearthed and placed on display. Ossuarive de Douaumont at Verdun, France.Photo 23. Chemicals from a German field hospital from WWI, near Verdun. Chemicals unearthed and placed on display. Ossuarive de Douaumont at Verdun, France.

Table of Tables

Table 1. Generic Chemical Interaction Matrix.Table 2. Most commonly used instrumental analysis methods.Table 3. Labelled chemicals from Police Museum collection. Table 4. Chemicals from the Police Technical Department of Helsinki.Table 5. Chemicals from field laboratory bag A.Table 6. Chemicals from field laboratory bag B.Table 7. Characteristic IR absorption for chemical named “Siansappi viinan”.Table 8. pH of chemicals from field laboratory bag A.Table 9. pH of chemicals from field laboratory bag B.Table 10. Results of X-ray fluorescence analysis for solid chemicals from the Police Museum.

A1-1

Appendix 1. European hazard symbols

(Directive 67/548/EEC)

Oxidizing agent (O) Explosive (E) Highly flammable (F) Extremely flammable

(F+)

Toxic (T) Very toxic (T+) Harmful (Xn) Irritant (Xi)

Corrosive (C) Dangerous for the environment (N)

A2-1

Appendix 2. Common hazard symbols

Name Symbol Unicode Image

Toxic sign ☠ U+2620

Caution sign ☡ U+2621

Radiation sign ☢ U+2622

Ionizing radiation sign

Non-ionizing radiation sign

Biohazard sign ☣ U+2623

A3-1

Appendix 3. IR spectra of chemicals from the collection of the Police Museum in

Tampere and their analysis

1. Antharcene

Chemical formula of anthracene

ATR-IR-spectra of anthracene technical from the collection of the Police

Museum in Tampere

A3-2

2. Zinc SilicateZn2SiO4 – chemical formula of zinc silicate

ATR-IR-spectra of zinc silicate from the collection of the Police Museum in

Tampere

A3-3

3. Silver Nitrate, AgNO3 - chemical formula of silver nitrate

ATR-IR-spectra of silver nitrate from the collection of the Police Museum in

Tampere

IR spectrum of Silver Nitrate according to www.webbook.nist.gov/chemistry

(applied 31.12.2007

A3-4

4. Naphtylamine-4sulphonic Acid

Chemical formula of naphtylamine-4sulphonic acid

ATR-IR-spectra of naphtylamine-4sulphonic acid from the collection of the

Police Museum in Tampere.

IR spectrum of naphtylamine-4sulphonic acid

according to www.webbook.nist.gov/chemistry (accessed 31.12.2007

A3-5

5. Peroxide 3%

ATR-IR-spectra of peroxide 3% from the collection of the Police Museum in

Tampere.

A3-6

6. ParaffinCnH2n+2 – chemical formula of paraffin

ATR-IR-spectra of paraffin from the collection of the Police Museum in

Tampere.

IR spectrum of paraffin according to www.webbook.nist.gov/chemistry

(accessed 31.12.2007)

A3-7

7. GlycerineC3H5(OH)3 – chemical formula of glycerine

ATR-IR-spectra of glycerine from the collection of the Police Museum in

Tampere.

IR spectrum of glycerine according to www.webbook.nist.gov/chemistry (accessed

31.12.2007).

A3-8

8. AcetoneCH3COCH3 – chemical formula of acetone

ATR-IR-spectra of acetone from the collection of the Police Museum in

Tampere.

IR spectrum of acetone according to www.webbook.nist.gov/chemistry

(accessed 31.12.2007).

A3-9

9. Neo-AmiseptNeo-Amisept contains: ethanol, isopropanol, glycerine.

ATR-IR-spectra of Neo-Amisept from the collection of the Police Museum in

Tampere.

A3-10

10. Malachite Green

- chemical formula of Malachite Green

ATR-IR-spectra of Malachite Green from the collection of the Police Museum

in Tampere.

IR spectrum of Malachite Green according to www.webbook.nist.gov/chemistry

(accessed 31.12.2007).

A3-11

11. Fuchsine

- chemical formula of Fuchsine

ATR-IR-spectra of Fuchsine from the collection of the Police Museum in

Tampere.

IR spectrum of Fuchsine according to http://search.be.acros.com/ (accessed

31.12.2007).

A3-12

12. Tetrabromphenolsulfophtalein

chemical formula of etrabromphenolsulphophtalein

ATR-IR-spectra of tetrabromphenolsulphophtalein from the collection of the Police

Museum in Tampere.

IR spectrum of tetrabromphenolsulphophtalein according to

http://search.be.acros.com/ (accessed 31.12.2007).

A3-13

13. Clove Oil

ATR-IR-spectra of clove oil from the collection of the Police Museum in Tampere.

IR spectrum of clove oil according to http://www.irug.org/ (accessed

31.12.2007).

A3-14

15. Jodicalium

ATR-IR-spectra of jodicalium from the collection of the Police Museum in

Tampere.

A4-1

Appendix 4. Characteristic IR Absorption by http://orgchem.colorado.edu/

(accessed 2.1.2008)