Paper Chromatography Lab

Paper Chromatography Lab

Chromatography Lab


Before we start, let us tell you a little bit more about what chromatography actually is and why it is used.


About Chromatography:


Chromatography is a procedure that is used to separate mixtures. This involves passing a mixture through a stationary phase, also known as a "mobile phase". As the mixture goes through the mobile phase, subtle differences in concentrations of each part of the mixture. It was first used in the mid 19th century primarily to separate plant pigments, most likely chlorophyll. It is attributed to Russian botanist Mikhail Semynovich Tsvet who used columns of calcium carbonate for seperating plant pigments during the first decade of the 20th century during his research of chlorophyll.



Reasoning for Experiment:

This experiment is to help us learn more about the bonds of different mixtures and compounds


Problem Statement:

Compare different solvents' polarity and ability to separate a mixture into its pure components.

Hypothesis:

Due to its attractive force that would allow the solution to move up the paper, we believe water will extract the solvent, moving the ink up the chromatography paper.

Materials:

Solvents - H₂O (water), CH₃OH (methanol), C₃H₇OH (propanol), and C₆H<sub>14 (hexane)

Mixtures - Water-soluble overhead pens (black, red, green, blue, and yellow)</sub>

24-well plate

Chromatography paper strips (1 cm x 8 cm)

Safety materials (apron and goggles)


Procedure:

PART 1

Before you start the lab, put on safety apron and goggles to prevent injury to hazardous material. Be careful, some of the mixtures are dangerous and should be used under a fume hood. First of all, cut chromatography paper into 1 cm x 8 cm strips. Fold the strip about 1.5 cm from one end. Put a pencil line near the crease and dot black marker across the pencil line. Be sure to allow the ink to dry. Label each strip on the opposite end with a pencil. Then, fill 4 separate wells on the 24-well plate approximately half full of the following solvents.

H₂O, CH₃OH, C₃H₇OH, and C₆H_{14. (Beware, some of these fumes can be dangerous)}

Next, place the chromatography paper strips into the solvent, not allowing the marker dots to be inserted into the solvent. Last of all, record your observations as you let the solvent to wick up the paper for 1/2 hour.

PART 2

Choose the solvent that best separated the ink's pigment from PART 1 and test its ability to separate different colors. Obtain 4-5 strips of chromatography paper, depending on how many colors you have, repeating the steps for labeling and adjusting the strips. Next, fill that many separate wells of the 24-well plate with a single solvent 1/2 full. Place the strips into the solvent, not allowing the marker spots to enter the liquid. Again, allow the solvent to wick up the paper for 1/2 hour. Record observations, sketching the results as shown for water.

Results:

As you can see in the photo above, red and green ink seem to have a variety of pigments compared to blue and yellow, which consist of only its own color.

Conclusion:

After experimenting with the solvents and inks, we conclude that our hypothesis is correct. Water transferred the ink up the chromatography paper the most effectively out of all the solvents.

Listed from best to worst solvents: H₂O, CH₃OH, C₃H₇OH, and C₆H14

From doing this lab, we learned about chromatography paper and its ability to reveal information about certain solvents.

Anomalies

This Experiment could have been more interesting and a learning experiment if we had a wider range of colors and chemicals to work with.