Internal Standard Analysis of Marshmallow Peeps

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 24 (2019) pp 188-190

Internal Standard Analysis of Marshmallow Peeps

Willis B. Jones^†, Clifton P. Calloway, Jr.^‡, and Bradley T. Jones*^,†

^†Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina 27109, jonesbt@wfu.edu;^‡ Department of Chemistry, Physics and Geology, Winthrop University, Rock Hill, South Carolina 29733
Received October 3, 2019. Accepted November 11, 2019.

Published: 31 December 2019

Abstract. 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%.

Key Words: Laboratories and Demonstrations; general chemistry; analytic chemistry

(*) Corresponding author. (E-mail: jonesbt@wfu.edu )

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Supporting Materials:

The Laboratory Instructions for this experiment are given in the Supporting Material. The preparation required for the experiment is minimal; the dye stock solutions are prepared as described above. While Marshmallow Peeps are a seasonal product in stores, they may be acquired online year-round. Step 2 in the instructions is crucial for the students. Errors occur if they select an unsuitable internal standard. Students may have questions at Step 3 as well. Neither the mass of the Marshmallow Peep nor the exact volume of water added needs to be known (this, indeed, is the beauty of the internal standard method). (357 KB)