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Things You'll Need
Instructions
Label each strip of chromatography paper with the name of the M&M color or food dye color that will be used. Use a pencil because ink from a pen will run and will ruin the experiment. There should be five strips for each color of candy you want to test. Draw a line across the width of the strip at 2 cm from the bottom.
Place a single drop of water on a plate and put an M&M on the drop. Allow the dye to dissolve in the water for a minute. Discard the candy.
Dip a toothpick into the water/dye mixture and transfer a drop to the center of the line drawn across the chromatography strip labeled with the corresponding color. Allow the spot to thoroughly dry. Repeat this step three or more times to ensure there is enough dye for the experiment. Use this procedure to make four more strips of the same color. Make five strips for each M&M color that will be your "unknown" candy dyes.
Place a single drop of food coloring on a plate. Dip a toothpick into the drop and transfer it to the center of the line drawn across a fresh chromatography strip. Allow it to dry and repeat with three or more drops. Make four more strips of this color. Use this procedure to make five strips for each color of food coloring.
Prepare the chromatography solvent by filling the beaker with 1 liter of water and adding 1 gram of salt to make a 0.1 percent salt solution. Stir until the salt dissolves completely.
Tape one end of a chromatography strip around the pencil. Pour enough solvent (the 0.1 percent salt solution) into the wide-mouth jar so that when the pencil is laid across the mouth of the jar, the bottom of the strip barely touches the surface of the water.
Place the pencil across jar so the strip touches the solvent. Watch the strip carefully and remove it from the jar just before the solvent reaches the top of the strip. Mark this level with the pencil. Allow the strip to dry. Repeat this step until you have run all the strips, adding more solvent to the jar as needed.
Calculate the retention factor (rf) of each strip. This is a ratio between the distance traveled by the dye sample and the distance traveled by the solvent. Measure from the original dye spot on the pencil line to the center of the new position of the dye spot. Rf = distance traveled by the dye/distance traveled by the solvent. If the dye traveled 2.5 cm and the solvent traveled 5 cm, the rf value is 0.5 (rf = 2.5/5.0 = 0.5).
Compare the rf of the "unknown" dyes with the rf of the food colorings. See if you can determine which ones were used in the various colors of the candy shells.