After I chose my project, I did as much research as I could to learn about chromatography and the different food dyes. As I did my research, I came up with questions that needed to be answered. I got several e-mail addresses from the web, from bulletins with questions similar to some of mine, and from the people who had written to answer them. I also contacted my father's thesis advisor, Professor Klock, at the University of Illinois at Urbana-Champaign, who was able to give me several e-mail addresses of chemistry professors on the campus, and of friends he has who might be able to help me. One of my parent's good friends, Dr. Robert Mustacich, was also able to help me answer some of my questions because he is considered one of the world's experts on chromatography.
As the time to start experimenting drew nearer, I bought liquid food colors and paste food colors, to use as my controls. These food colors are used to color frosting and candy. I also purchased a roll of chromatography paper and a Thin-Layer Chromatography kit. The kit that I purchased was designed for use in high school chemistry classes. I performed several tests with the chromatography paper and with the liquid and paste food dyes, using distilled water as the solvent. Then I decided to follow some of the advice from the people who had been answering my questions and try different solvents. Along with the distilled water, I used ammonia, white vinegar, and a 5% NaCl solution with distilled water. Some of these worked better than others with certain dyes.
After testing all the different liquid and paste food dyes in the four different solvents, with two different types of paper, I was ready to test the candy that I had chosen. This was tricky because I had to remove the dye from the shells of the candy bits without getting any of the white layer or the chocolate middle. The first method I tried was dissolving the candy coating in distilled water. This was unsatisfactory because the dyes were not concentrated enough and did not give good chromatographic results. The second method came from one of my web sources and provided a technique for dye extraction that worked very well. At this time, I also decided to try the Thin-Layer Chromatography kit. The thin-layer chromatography worked very well for the standards and this is the method that I used to test the dyes in the candy bits that I had chosen.
After researching food dyes and chromatography, I wrote my report, put
together my presentation board, and designed and wrote my web page.
Project researched and
documented by Ann VanBlaricum
Disclaimer: These pages were written in 1997 while the author was a sophomore in high school taking AP Chemistry. Hence, the author is not an expert on this subject, she cannot vouch for the accuracy or currency of these data or the links.