Analysis of Caffeine in Beverages: Using Aspirin as a Fluorescent Chemosensor

作者：Smith Jordan; Loxley Kristen; Sheridan Patrick; Hamilton Todd M^*

来源：Journal of Chemical Education, 2016, 93(10): 1776-1780.

DOI：10.1021/acs.jchemed.6b00303

• Upper-Division Undergraduate
• Analytical Chemistry
• Laboratory Instruction
• Physical Chemistry
• Hands-On Learning
• Consumer Chemistry
• Drugs/Pharmaceuticals
• Fluorescence Spectroscopy
• Medicinal Chemistry
• Quantitative Analysis

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.

• 出版日期2016-10