Determining the Color Dyes in Candy Coatings by Using Paper Chromatography

Determining the Color Dyes in Candy Coatings by Using Paper Chromatography

Introduction:

The experiment uses paper chromatography to find Rf values of different food dyes and determine the food dyes used in the colored coatings of candy and a Kool-Aid solution. Paper chromatography is a type of liquid chromatography that uses paper as the stationary phase. The analyte is directly applied to the bottom of the paper and then put in a developing tank so the bottom is submersed in the mobile phase, but not the spots of analyte. Capillary action pulls the mobile phase up the paper carrying along the different dyes. The positions of the components are marked to be able to find the Rf values. The main principle is partition as the components separate as they go up the paper at different speeds. The objective of this experiment is to determine Rf values of solutions and food dyes in candy coatings and Kool-Aid by paper chromatography.

Mathematical Equations:

Rf = Distance Solute MovedDistance Solvent Moved

Experimental Section:

This experiment uses 0.10% Sodium Chloride solution for the solvent in the mobile phase, Red No. 40, Red No. 3, Yellow No. 6, Yellow No. 5, Blue No. 1, Blue No. 2, Kool-Aid solution, a Red M&M, and an Orange M&M. The first step was to prepare 9 capillaries and pour a few mL of 0.10% NaCl solution into a 100 mL beaker that is immediately covered with a 400 mL beaker. The paper’s were then prepared by drawing horizontal lines 1.0 cm from the top and bottom and vertical ticks on one of these lines that were 0.5 cm apart. A capillary was used to apply each standard dye solution spot and let dry then reapplied about 2 more times until they were dark enough. The paper’s were then placed in the developing tank and let sit until the solvent reached the top horizontal line. The positions of the darkest part of each component were then marked and measured. After, the Rf values were calculated and the chromatograms were looked at under a UV lamp to determine their fluorescence. Next, the candy solutions were prepared by placing the individual candies in beakers and mixing them with about 1 mL of a 50/50 ethanol and water mixed solution until the coating was dissolved. The Kool-Aid was then spotted in the same way as the standard dye solutions and the candy solutions were spotted about 6 times or until they were dark enough. The last chromatogram was then developed and each dye was characterized by Rf values, color