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1 Mixtures and Solutions: Candy Chromotography Background Information and Research Biochemists often use this method of separation when studying amino acids or other chemicals from living things. Also they use it to separate a solution with multiple components with different polarites. People use chromoography to find the things in milk,find out what chemicals are in black ink, also determine whether something is hazardous or not. Purpose The purpose of this experiment is to see what kind of dyes and colors are in the candy’s colored coating. Also to see what kind of things are in it. Materials: Candy with a colored coating, like Skittles ® or M&Ms ® (4 different colors) †¢ Rubbing alcohol or isopropyl alcohol †¢ Coffee filters (2) †¢ Tall glasses or plastic cups (2) †¢ Pencil †¢ Ruler †¢ Tape †¢ Foil or paper plate †¢ Table salt †¢ Water †¢ Toothpicks or cotton swabs (4) †¢ Measuring cups/spoons †¢ Clean pitcher or 2-liter bottle Procedure: 1. Coffee filters usually are round, but it's easier to compare your results if the paper is square. So your first task is to cut the coffee filter into a square measuring three cm by nine cm square from a coffee filter. You will need two of these strips to complete the lab. 2. Space four drops of water (or however many colors you are testing) equally distant on a piece of foil or plate. Position one candy of each color on the drops. Give the color about a minute to come off into the water. Dispose of the candy. 3. Using a pencil (do not use a pen), draw a line one cm (1/2 inch) from the edge of one end of one strip of paper. 4. Make four pencil dots (one for each color of candy you will be examining) along this line, about 0. cm (1/4 inch) apart. Underneath each dot, label the color of the candy you will test on that spot. You won't have space to write the whole color name, so try abbreviations like B for blue, G for green, etc. 5. Before you complete the rest of the lab, make a prediction of the components you expect to see from each candy color. 6. Dip a toothpick or cotton swab into one sample of colored water and dab the color onto the pencil dot for that color. Use a clean toothpick for each co lor. Try to keep each dot as small as possible. Allow the filter paper to dry, and then go back and add more color to each dot, repeating this step a total of three times for each color. 7. Prepare the salt solution by mixing 1/8 teaspoon of salt and three cups of water in a clean pitcher or 2-liter bottle. Stir or shake the solution until it is dissolved. This will produce a 1% salt solution. 8. Pour the salt solution into a clean tall glass so that the liquid level is 1/4 inch (0. 5 cm). 9. Tape the strip to a pencil and rest the pencil on top of the jar so that the strip hangs into the jar. The goal is to have the end of the chromatography strip just touching the surface of the solvent solution, with the colored dots above the surface of the liquid. Make sure that the colored spots do not come in direct contact with the liquid in the bottom of the glass. 10. Capillary action will draw the salt solution up the paper. As it passes through the dots, it will begin to separate the dyes. When the salt water is 1/4 inch (0. 5 cm) from the top edge of the paper, remove it from the glass and place it on a clean, flat surface to dry. 11. Repeat steps two through nine (using the second strip of paper and a clean glass) to test the same four colors using the alcohol instead of the saltwater solution at the bottom of the glass. Data and Observations Original Predictions: †¢ The red M&M will travel the farthest and be the strongest. †¢ The The dye in the yellow M&M will travel less and be the lightest color. †¢ [pic] Other observations I noticed was the stationary phase matters. Both the red and yellow travveld to the front but had little separation. Red showed the lowest travelling distance. Discussion and Conclusion: The first part of this section discusses the observations and results of the lab as well as any mistakes that may have been made (or what measures were taken to try to avoid mistakes) and what improvements, if any, you can think of for the procedure for the next time the lab will be conducted. The discussion section of this lab should also include discussions on the following: †¢ A comparison of how each solution (salt water and alcohol) separated the pigments from each color of candy or ink type. Which solution worked better at separating each of the pigments (it may be different for different candy colors or inks), and why do you think that is? †¢ If you had allowed less time for the lab (stopping the separation process when the solution was half way up the paper) how do you think that would have affected your results? †¢ What pigment colors traveled farther up the paper? What pigment traveled the least? Was it the same or different when those pigments appeared in other candy colors or inks? Was it the same or different when separated by alcohol instead of salt water?