Lab glass cleaning

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Lab Glass Cleaning.com

Advicefor clean and residue freeresidue-freelaboratoryequipment

© Dr. Weigert & DURAN Group 2012

Good practice– type of glass.com

Good practice type of glass

Selection of right types of glass

a high quality of the raw materials and their i icomposition

wall thickness distribution in order to attain a good resistance to temperature and g pchanges in temperature, high level of mechanical stability

a very high hydrolytic resistance a very high hydrolytic resistance (corresponds to class 1 according to ISO 719).

very small expansion coefficients, a high level of resistance to quick changes in temperature


Good practice– conformity to standards.com

Good practice conformity to standards

• Why should attention be paid to conformity to standards?

standards set the properties and standards set the properties andgeometries for laboratory glass products -> products can be still be obtained with thesame characteristics and dimensionssame characteristics and dimensions even after many years

characteristics which are decisive for safety such as distribution of wall thickness in beakers, are given in the standards for many articles


Good practice– instruction for use.com

Good practice instruction for use

• What is important when selecting a glass item for use?

before each use the glass surface should be before each use the glass surface should be checked for damage such as scratches, cracks or chips

l h ld l b d h h vessels should only be used when they are in a flawless condition, this is particularly important for work under pressure or at high temperatures

damaged glass may not be used for safety reasons.


Cleaning – cleaning process.com

Cleaning cleaning process

The advantage and disadvantages of

• manual cleaning greater risk of injury

slower and less economical when there are lots of items to be washedare lots of items to be washed

time consuming when the laboratory appliances have a complex geometry

is clearly quicker if only single laboratory glass items are being cleaned

flexible in terms of duration of cleaning flexible in terms of duration of cleaning and selection of cleaning agent


Cleaning – cleaning process.com

Cleaning cleaning process

Advantages and disadvantages of• cleaning in a washer/disinfector

reduced breakage risk reduced breakage risk

reduced risk if injury

saves staff resources

quicker and more economical for large quantities of items to be washedwashed

inflexible in terms of duration of cleaning and selection of cleaning agent


Cleaning – type of soiling.com

Cleaning type of soiling

Type of soiling

• Organic soiling

peptides/ proteins, fats/oils, carbohydrates/ polysaccharides, organic colourings pigment residuesorganic colourings, pigment residues and felt tip residues, resins and paraffin




Type of soiling

• Inorganic soiling g g

carbonates, salts, metal oxides, watery solutions of inorganic acids(HCl H SO )/(HCl, H2SO4)/ alkali (NaOH, KOH), salt solutions(NaCl, NaNO3, FeCl2 etc.)




Type of soiling

• Microbiological residueg

growth media, cell cultures and tissue residues, nutrient broth,

i imicroorganisms


Cleaning - cleaning agents.com

Cleaning cleaning agents

Which cleaning agents are suitable for which soiling?

• Alkaline cleaning agents it bl f th d t i d l are suitable for the denaturing and removal

of residues which contain protein, fat and carbohydrates

• Acid cleaning agents are effective against inorganic salts,

lime and other carbonates.

• Bleaching agents help with the removal of paints and with disinfection.


Cleaning - cleaning agents.com

Cleaning cleaning agents

• What requirements must a cleaning agent meet? The selection is linked to the type of soiling to

b d d th f k diti (tibe removed and the framework conditions (time, material properties and mechanical system, qualityof water)

fundamental requirements:

good ability to remove dirt

high dirt carrying capacity

• Which resources can be used?

abrasive materials (steel wool) high dirt-carrying capacity

suitable for most surfaces

good rinsing properties

must not be used -> these will cause surface damage to the glassg g p p

not hazardous to health

very cost-effective

soft sponges, cloths and brushes are suitable


environmentally friendly

Cleaning – parameters of cleaning.com

Cleaning parameters of cleaning

• Chemistry (=cleaning agents) helps with the decomposition of dirt

t d th i lificomponents and thus simplifies the removal of dirt from surfaces

the surfactants contained in cleaning agents improve the wetting of the item to be cleaned and the dirt-carrying capacity of the watercapac ty o t e ate

the selection of the cleaning agent to be used depends on the dirt to be removed the material of the items to beremoved, the material of the items to becleaned and the quality of water used for automated cleaning




• Temperature high temperatures can accelerate physical,

h i l d ti dchemical and enzymatic processes and thus benefit removal of contaminations

temperatures which are too high can,

however, reduce enzyme activity

Another disadvantage of excessive temperature i th i f b i id t i d iis the conversion of carbonic acid contained in the water to carbonate via hydrogen carbonate which is then precipitated as a poorly soluble compound with the water hardening salts magnesium and calcium. This results in stubborn ‘lime deposits’.




• Time an extended reaction time for the

l i l ti k th lcleaning solution makes the removal of dirt from the surface easier due to better swelling of the contaminants and a stronger chemical decompositionof the dirt components




• Mechanics The use of mechanical agents such as the

f b h duse of brushes or pressurized water jets enables bonding forces between dirt and surface to be overcome so that dirt can then be removed more easily.

Chemistry temperature time and mechanics are the four components Chemistry, temperature, time and mechanics are the four components of the so-called Sinner’s Circle which describes the mode of action of the cleaning process and which was named after the chemist Dr. Herbert SinnerSinner.


Cleaning – Dr. Sinner´s Circle.com

Cleaning Dr. Sinner s Circle

Dr. Sinner’s Circle

Each parameter is variable in size. However, if one factor is changed this will affect the size of at least one other factor if the cleaning performance is to remain the same. This means that a longer reaction time is necessary if there is a lower temperature in the rinsing process for example. A reduced parameter is thus compensated by the increase of another.


Cleaning – quality of water.com

Cleaning quality of water

Quality of water

defines

• microbiological factors (germ count)

• the degree of water hardness, given in °GH (German hardness) (magnesium and calcium ions in the water )(magnesium and calcium ions in the water )

If water with a high degree of hardness is used for cleaning, significant residues may be deposited on the cleaned surfaces

Depending on the water quality (e.g. deionised water or softened water) different effects are achieved in combination with the used cleaning agents. These affect the material compatibility and the cleaning results.


Advice and Tips• How can laboratory glass be stored correctly

.com

Advice and Tips• How can laboratory glass be stored correctly

whilst saving as much space as possible?

• Marking – what has to be observed?

• How can stubborn residues be avoided?

• How should the glass be disposed of?

• What should you know about volumetric• What should you know about volumetric glassware?

• How should you clean cover glass and slides?

All this and more at :

www.labglasscleaning.com


Laboratory Glass Cleaning.com

Laboratory Glass Cleaning

From experts for experts –p p© Dr. Weigert & DURAN Group 2012

www.labglasscleaning.com

Pictures by Karin Gerdes


Pictures by Karin Gerdeshttp://www.karingerdes.de

Lab glass cleaning

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