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The Chemical Educator

ISSN: 1430-4171 (electronic version)

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Abstract Volume 8 Issue 3 (2003) pp 201-205

Simultaneous Determination of Caffeine in Cola Drinks and Other Beverages by Reversed-Phase HPTLC and Reversed-Phase HPLC

Peter Kusch* and Gerd Knupp

Department of Biology, Chemistry, and Materials Science, Fachhochschule Bonn-Rhein-Sieg, University of Applied Science, von-Liebig-Str. 20, D-53359 Rheinbach, Germany, peter.kusch@fh-bonn-rhein-sieg.de
Received December 17, 2002. Accepted February 13, 2003

Published online: 11 April 2003

Abstract. A simple reversed-phase high-performance thin-layer chromatographic (HPTLC) method for the identification and quantitative determination of caffeine in Coca-Cola is described. The chromatographic conditions of the HPTLC method are further adapted by developing the HPLC method for identification and determination of caffeine in cola drinks and other caffeine-containing beverages. The results of the quantitative determinations of caffeine in Coca-Cola obtained by using both HPTLC and HPLC methods were 96.1 ± 1.1 mg L1 and 95.4 ± 0.2 mg L1, respectively. The experimental objective for the students is to determine the unknown amount of caffeine in a complex matrix by two different chromatographic techniques. The pedagogical objective is to make students familiar with these well-established techniques. Furthermore, they learn about the usefulness, difficulties, and limitations of comparative analytical studies. The two-part experiment has been developed for second-year chemistry and biology undergraduate students and is performed in the instrumental analysis course in two three-hour laboratory sessions.

Key Words:  Laboratories and Demonstrations; instrumental analysis; HPTLC; HPLC; caffeine-containing drinks

(*) Corresponding author. (E-mail: peter.kusch@fh-bonn-rhein-sieg.de)

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Issue date: June 1, 2003

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