Experiments involving the determination of FD&C food dyes present in various foods are simple and easy to prepare for introductory level chemistry laboratories. The use of commercial samples demonstrate real world applications of analytical chemistry and the brightly colored solutions keep experiments engaging for students in some of their earliest laboratory experiences. The experiment presented here investigates the amount of food dye present in Peeps brand marshmallow chicks. Peeps are bulky and inhomogeneous, making sample preparation difficult, especially for introductory level chemistry students. However, these problems make Peeps an ideal candidate for the internal standard method. The nature of the data analysis allows for the mass of dye present in each peep to be determined without the need for volumetric glassware. The amount of Blue 1 dye present in blue, Red 3 in pink, and Yellow 5 in yellow Peeps is found to be 225, 370, and 940 μg, respectively. The relative standard deviation in each case is on the order of 5%.
Jones et al. (Fri,) studied this question.