Food Dyes Lab

The Chromatography of Food Dyes and determination Of the Dyes Present in M&M Candies

Procedure

To complete this lab, I first mixed the solvent solution consisting of the proper ratio of water, salt, and isopropyl alcohol in a Pyrex measuring cup. I then prepared my chromatography papers for 2 trials by drawing, with a pencil, the appropriate lines and labels. Using a toothpick, I added the color to the paper, and then repeated until the color was strong. I repeated this step several more times for the M&Ms as the color solution was not as strong as the food dyes. After the dyes were dry, I rolled the paper and added it to the pie plate, which contained a small amount of the prepared solvent. I then waited for the solution to
reach the line I had drawn approximately 2/3 of the way up the paper. This step took about an hour. After that, I removed the paper and marked the position of each dye. I repeated this whole procedure for a second trial. At this point, I measured and calculated the Rf values.
M&Ms Color | Solvent frontT1 T2 | Distance Trial 1 | DistanceTrial 2 | Rf ValueTrial 1 | Rf valueTrial 2 | brown | 13.1/12.8 | 6.2cm | 6.9cm | .473 | .540 | orange | 13.1/12.8 | 7.3cm | 11.4cm | .556 | .892 | blue | 13.1/12.8 | 11cm | 11.8cm | .840 | .922 | red | 13.1/12.8 | 4.9cm | 6.4cm | .374 | .500 | green | 13.1/12.8 | 7.4cm | 6.7cm | .565 | .523 | yellow | 13.1/12.8 | 10.2cm | 10cm | .779 | .781
|

Food Dye color | Solvent frontT1/T2 | DistanceTrial 1 | Distance Trial 2 | Rf ValueTrial 1 | Rf ValueTrial 2 | green | 13.1/12.8 | 9.9cm | 11.5cm | .756 | .898 | blue | 13.1/12.8 | 9.8cm | 10.4cm | .748 | .813 | red | 13.1/12.8 | 3.4cm | 4.2cm | .300 | .328 | yellow | 13.1/12.8 | 9.8cm | 10.5cm | .748 | .820 |

Analysis and Evaluation of Results

The affinity of a substance for the stationary and mobile phases is characteristic of that substance.
Different dyes have different affinities. Since each component of a dye has its own distinctive affinities, each component will travel up the paper at its own rate. It seems from my results that blue has an affinity for the mobile phase as it quickly moved up the paper with the solvent. Red, on the other hand, seemed to have an affinity for the paper, as it did not travel as far as the other colors.

Post Lab Questions 1. I do believe the ingredients in the food dyes effected the rate of movement. While the Rf rates were somewhat similar between the candies and the food dyes, For the most part the M&Ms did not move as far as the food dyes. This could be because the color was more concentrated in the bottled dyes. 2. The green colors of both the dyes and the yellow M&M contain yellow #5. 3. Persons with an allergy to tartazine should avoid both yellow and green M&M candies. 4. I did correctly guess that green dye might contain
yellow.