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ERIC Number: EJ1117359
Record Type: Journal
Publication Date: 2016-Oct
Pages: 5
Abstractor: As Provided
ISSN: ISSN-0021-9584
Analysis of Caffeine in Beverages Using Aspirin as a Fluorescent Chemosensor
Smith, Jordan; Loxley, Kristen; Sheridan, Patrick; Hamilton, Todd M.
Journal of Chemical Education, v93 n10 p1776-1780 Oct 2016
Caffeine (1,3,7-trimethylxanthine) is an alkaloid stimulant that is popular in beverages. Fluorescence-coupled methods have been used to measure the caffeine content in coffee, tea, soft drinks, energy drinks, and cosmetics. In this experiment, we have developed a method for detecting caffeine in beverages utilizing the effect of the caffeine concentration on the fluorescence of acetylsalicylic acid (aspirin). Caffeine quenches the fluorescence of aspirin and the resulting Stern-Volmer plot from caffeine standard solutions can be used as a calibration curve. This method meets the criteria for fast, sensitive, and convenient caffeine detection. The caffeine concentration values in avitae caffeine water samples and Ale-8-One ginger ale beverage were in quantitative agreement with the reported values, within experimental error. This method can be extended to other caffeinated beverages that are clear or have an overall light color. This experiment is appropriate for the physical chemistry laboratory, the analytical chemistry laboratory, and the medicinal chemistry laboratory. Instructors may find the framework useful for teaching concepts in fluorescence spectroscopy and quenching, as well as the analysis of active ingredients in food products and cosmetics.
Division of Chemical Education, Inc and ACS Publications Division of the American Chemical Society. 1155 Sixteenth Street NW, Washington, DC 20036. Tel: 800-227-5558; Tel: 202-872-4600; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Higher Education; Postsecondary Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Grant or Contract Numbers: N/A