Separation of Food Colorings via Liquid–Liquid Extraction: An At-Home Organic Chemistry Lab

• Published in: Journal of chemical education Vol. 98; no. 3; pp. 951 - 957
• Main Authors: Orzolek, Brandon J, Kozlowski, Marisa C
• Format: Journal Article
• Language: English
• Published: Easton American Chemical Society and Division of Chemical Education, Inc 09.03.2021; Division of Chemical Education, Inc; American Chemical Society
• Subjects: Chemistry; College Science; College students; Experiments; Extraction processes; Family Environment; Food; Food dyes; Hands on Science; Home environment; Laboratory Experiments; Laboratory Safety; Organic Chemistry; Safety; Science Experiments; Science Instruction; Science Laboratories; Separation; Sodium bicarbonate; Solubility; Students; Studies; Teaching Methods; Undergraduate Students; Vegetable oils; Vinegar; Hands-On Learning/Manipulatives; Laboratory Instruction; Acids/Bases; Separation Science; Second-Year Undergraduate; Organic Chemistry; Dyes/Pigments; Physical Properties
• ISSN: 0021-9584; 1938-1328
• DOI: 10.1021/acs.jchemed.0c01286

Herein, we describe an accessible and safe organic chemistry lab experiment that can be completed at home. Liquid–liquid extraction is a fundamental organic chemistry lab experiment that touches on topics such as chemical structure, density, solubility, and acid–base chemistry. Given the increased demand for safe organic chemistry experiments that can be performed in the at-home environment, we have adapted the conventional wet lab liquid–liquid extraction experience by using food colorants. Students are first guided through sample questions to establish a basic understanding of solubility, acid–base chemistry, and separation via extraction techniques. Next, they are given unknown dye mixtures which they subject to liquid–liquid extraction using a plastic soda bottle with vegetable oil, water, white vinegar, and sodium bicarbonate. All materials are readily available and food-safe, making the experiment amenable to the at-home environment while still allowing students to physically engage in a foundational lab experiment.