Name: ___________________________
Date: _________________ Period: ____
Paper Chromatography Lab
Testable Question: How can chromatography be used to separate mixtures?
Background Information: Paper chromatography is a technique used to separate colored chemicals. The
colors in your pens and markers are a mixture of different colors. In paper chromatography substances are
distributed between a stationary phase and a mobile phase.
 The stationary phase is usually a paper strip.
 The mobile phase is a liquid solvent (water or rubbing alcohol) that travels up the stationary phase,
carrying the samples with it.
 Components of the sample will separate according to how strongly they absorb on the stationary
phase versus how easily they dissolve in the mobile phase.
 Usually larger molecules will be trapped on the stationary phase and smaller molecules will move
more readily with the solvent.
 Different types of molecules move different distances with solvents. Generally, the longer molecules
can remain dissolved in the solvent, the farthest they can move. Less soluble molecules are left
behind, trapped by the fibers in the paper. This causes the components of the mixture to separate,
making a chromatogram.
o This technique is used to analyze
 dye composition,
 detection of pesticides or insecticides in foods,
 determine the presents of pigments from plants, and
 identifying compounds present in a given substance.
Today you will be comparing the chromatography of the ink from contaminated packaging of the salad to the
packaging of the 4 different farms that produce greens locally.
Materials for each group:
5 labeled (A, B, C, D, X) chromatography papers with ink samples in wax paper packets
5 ml water
Medicine cup
1 Beaker
5 tiny test tubes
1 plastic pipette
colored pencils
Tape
paper towel
Procedures:
1. Use the tape to label the 5 test A, B, C, D, and X (contaminated package).
2. Transfer 4 drops of water to each test tube. DO NOT ADD ANY MORE THAN 4 DROPS OR YOUR
RESULTS WILL BE INACCURATE.
3. Gently place the labeled paper samples into the test tube with the ink sample just touching the water.
4. Observe the colors that appear and record them in Table 1.
5. Once the leading color reaches the top of the paper take it out of the test tube and lay it flat on the paper
towel to dry. Put your names on the paper towel and tape down your results.
6. Create a copy of your chromotogram on Table 2 using the colored pencils.
1
Results:
Table 1: Record color that appears in order of appearance (if red separates first, label it 1, if green shows up
next, label it 2…) :
Pen/Ink
Pink
Red
Orange
Yellow
Green
Blue
Indigo/
Other
Sample
Purple
Contaminated
Salad
Packaging
(X)
Salad Bag A
Schneider’s
Salads
Salad Bag B
Kieffer’s
Keep
Salad Bag C
Endler’s
Endive
Salad Bag D
Godoy’s
Greens
Table 2: Histogram for order of color appearance:
Color Order
(Draw your
results using
colored pencils)
Contaminated
Salad
Packaging
(x)
Salad Bag A’s
(Schneider’s
Salads)
Pen/Ink Sample
Salad Bag B’s
(Kieffer’s Keep)
Pen/Ink Sample
Salad Bag C’s
(Endler’s
Endive)
Pen/Ink Sample
Salad Bag D’s
(Godoy’s
Greens)
Pen/Ink Sample
Summary Questions
Use your results and information from the background reading to help you answer these questions.
1. Identify the solute (dissolved substance) _______________________ and solvent (dissolving substance)
_________________________ used in this lab.
2
2. What caused the pigments to separate?
3. The contaminated salad packaging ink matched which salad bag’s ink? State evidence from your results
to support your answer.
Use the background information to help you answer these questions.
4. List 3 real world applications for chromatography.



5. Based on your observations in this lab, describe how chromatography works.
6. Why do certain colors stop at certain points and others continue to travel with the solvent?
7. What would happen if a farm used waterproof ink?
8. What solvent could we have used to see the same results?
3