Name ______________________
Paper Chromatography Lab
Chromatography is a useful method for separating the substances in a mixture. For any mixture the substances
are not chemically combined so they can be separated by simple physical methods, such a chromatography.
Chromatography works due to the differences in the size and charge of the molecules in the different substances
that we want to separate.
What is the purpose of this lab?
Procedure:
1. Get seven strips of chromatography paper.
2. Use a pencil to label the top of the paper with the type of pen and color of ink.
3. Use a pencil to draw a line across the paper, 2 cm from the bottom.
4. At the center of the pencil line make a good spot with a marker, corresponding to the color written at the
top of each of the papers.
5. Put just enough water in a beaker to cover the bottom.
6. Carefully stand each paper in a beaker and then tape it to a glass stirring rod that has been laid across the
top of the beaker. This will keep the paper from falling into the water. (See Figure 1.)
7. DO NOT ALLOW THE INK SPOT TO TOUCH THE WATER OR THE SIDES OF THE BEAKER.
8. Wait for the water (the solvent) to reach the top of the beaker. Record the colors you see, in the data
table. Make sure to list the colors from the bottom of the paper to the top.
9. Remove the strips from the water and un-tape them from the glass stirring rod.
10. Lay the strips on a small piece of paper towel to dry. Put your names on the paper towel and set it back
against the wall until tomorrow.
11. Clean up everything and put it back where it came from.
12. On day two, one person from the lab group will get the dried papers and attach them to their lab. THIS
PERSON MUST WRITE THE OTHER GROUP MEMBERS NAME’S ON THEIR LAB NEXT TO
THE PAPER STRIPS.
13. Everyone in the group should list on their lab who has the papers attached.
Attach dried chromatography papers here or write who has them.
________________________________________________________________
Questions: You must use complete sentences with proper grammar and spelling to answer these questions!
1. Why was a pencil used rather than a marker or pen to make the lines on the chromatography paper?
2. Did a chemical or physical change occur in this experiment? How do you know?
3. Did the darker or lighter markers tend to have the most colors in them? Why do you think it is this way?
4. Is there a pattern to how the colors moved up the paper? In other words, do the separated colors tend to
occur in a certain order?
5. Predict what would probably happen to an orange marker.
6. Read the wrapper on a bag of Skittles colored candy (see photo below). Are there colors listed as
ingredients other than the actual colors of the purple, blue, orange and lime green candies themselves?
Explain why we would expect different colors to be listed on the ingredients.
7. Explain why the ink from the regular ink pen did not separate in this experiment. How could we get it to
separate?
8. Explain why the ink from the permanent marker did not separate in this experiment. How could we get
it to separate?
9. Chromatography is used in forensic science to determine if a document has been forged or if the
signature on a check has been forged or changed. If part of a check was written with one black pen and
another part of the check was written with a different black pen (see photo below), what might the
forensic examiner be looking for in order to determine if the check is a forgery? Explain.
Ingredients: sugar, corn syrup, hydrogenated palm kernel oil, apple juice from concentrate, citric acid, dextrin,
gelatin, artificial and natural flavors. Coloring includes: yellow 5, yellow 6, blue 1 lake and red 40.
A forged check?
Chromatography Data Table
List the colors that appear in order, from the bottom of the paper to the top.
Ink type and color Observations: colors that appear in order from bottom to top
in each beaker
green marker
blue marker
red marker
purple marker
black marker
ball-point pen
permanent marker
Figure 1. Set-up for paper chromatography lab.
Paper strip
Glass rod
Glass stirring
rod
Marker dot
Water level