Determination of the Weight Percent of Dye in Marshmallow Candy Using External Standards and Standard Addition

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 22 (2017) pp 8-11

Determination of the Weight Percent of Dye in Marshmallow Candy Using External Standards and Standard Addition

Miranda S. Adams^†, Katrina Binaku^‡, and Thomas M. Spudich^†,*

^†Maryville University of St. Louis, 650 Maryville University Drive, St. Louis, MO 63141, tspudich@maryville.edu; ^‡Loyola University Chicago, 1032 W. Sheridan Rd., Chicago, IL 60660
Received August 26, 2016. Accepted October 5, 2016.

Published: 25 January 2017

Abstract. This experiment involves determining the weight percent of FD&C Yellow #5 in a marshmallow candy sample using external standard and standard addition methods. The procedure reported herein was developed for use in an undergraduate general chemistry or quantitative analysis laboratory course to provide a hands-on approach introducing both methods. Standard addition is a method used to correct for matrix effects in a solution among other issues. If an analyte is mixed with other materials, those other materials, referred to as a matrix, have the potential to affect the analytical method’s reliability with respect to sensitivity, selectivity, linear range, etc. The experiment illustrates to students a simple matrix correction in a tangible, inexpensive way using a sample likely familiar to the experimenter, a marshmallow candy. The range of weight percent FD&C Yellow #5 determined by students was 0.0057 to 0.241 using both methods. As a result of completing the experiment, students were able to achieve an understanding of both external standard and standard addition calibration methods. Students (1) developed an understanding of Beer’s Law and its application, (2) visualized and applied the methods of standard addition and external standards, and (3) developed sample and standard solution preparation skills. Students also gained ability to generate calibration curves and analyze experimental data to ultimately compare their weight percent of dye to the acceptable daily intake of FD&C Yellow #5.

Key Words: Laboratories and Demonstrations; analytical chemistry; quantitative analysis; spectroscopy; external calibration; standard addition; matrix effect; second-year undergraduate curriculum; student-centered learning

(*) Corresponding author. (E-mail: tspudich@maryville.edu )

Article in PDF format (143 KB) HTML format

Supporting Materials:

Photos of the materials used, the laboratory procedure given to students, example calculations for external standard and standard addition methods are included as supplementary material. (674 KB)