Monday 27 February Topic: Ink Chromatography

Monday 27 FebruaryTopic: Ink ChromatographyDO NOW:How would you describe ink to somebody that had never encountered it before? Be as detailed as you can!HW: Read the article “Drawing the Lines” and answer the prompts from the weekly sheet.

OBJECTIVE: You will be able to describe how ink chromatography is used as a form of document analysis.

What is ink?•Mixture•A liquid that contains pigments•Has many chemicals that contribute to its

properties:▫Color▫How smoothly it writes▫Smudginess▫How quickly it dries▫Sheen, etc


What is chromatography?•‘Chroma’ refers to colors•Process by which a substance is

separated into its constituent parts▫Each component is visible as a different

color


Chromatography Process•Small sample of the

substance to be analyzed is put onto filtration paper

•Paper is propped upright in a solution that will cause the components to separate

•Set-up is left alone for ~20-30 minutes so it can “run”


Image taken from sciencebuddies.org


Image taken from chemwiki.ucdavis.edu

Vocabulary:•Analyte: the substance to

be separated by chromatography

•Solvent: liquid that will go up the paper and separate the substances

•Chromatogram: results of the separated components


Exit ticket:•Answer the objective for today:

▫You will be able to describe how ink chromatography is used as a form of document analysis


Procedure:

WATER ACETONE

Sample of each ink, labeled in pencil as A, B, C, and D

Line drawn in pencil of where the sample starts

Filtration paper: either taped to a pencil or folded in half to stand up

Thursday 1 MarchTopic: Ink Chromatography

DO NOW:1. Why is it important to use 2 different solvents on the

same ink sample?2. Explain how to set up a chromatography analysis

experiment.HW: Complete analysis questions

OBJECTIVE: You will be able to identify a culprit by performing chromatography on a number of ink samples

OVERVIEW:•PER PERSON:

▫4 filter papers 2 for black inks, 2 for blue inks

▫2 beakers 1 with H2O, 1 with acetone•Can fold paper lengthwise to keep paper

upright•Be careful not to shake beaker


WATER ACETONE

2 of these in one beaker: one for blue ink and one for black

2 of these in one beaker: one for blue ink and one for black

Exit ticket1. Did any ink samples provide results in

both solvents? Why do you think this occurred?

2. Why might some smears of color be much longer than others?


HW = complete analysis q’s

Friday 2 MarchTopic: Ink Chromatography

DO NOW:1. Describe how accurate this type of analysis is in

terms of contributing it as evidence in a court case.

HW: 1. Footprints mystery article

OBJECTIVE: You will be able to 1) identify the culprit based upon the results of ink analysis and 2) demonstrate your understanding of ink analysis.

Results:•Difference of black ink samples in the 2

solvents:▫

•Difference of blue ink samples in the 2 solvents:▫

•Why some inks separated in both solvents:▫

•Why some color smears are longer than others:▫


QUIZ TIME!•Quiz is on ink analysis / chromotography

procedure only


Monday 27 February Topic: Ink Chromatography

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