Analytical Sciences

Simultaneous Determination of Trigonelline, Caffeine, Chlorogenic Acid and Their Related Compounds in Instant Coffee Samples by HPLC Using an Acidic Mobile Phase Containing Octanesulfonate

Kana ARAI,*1 Hiroyuki TERASHIMA,*2 Sen-ichi AIZAWA,*3 Atsushi TAGA,*4 Atsushi YAMAMOTO,*5 Kaname TSUTSUMIUCHI,*5 and Shuji KODAMA*1

*1 School of Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan
*2 GL Sciences Inc., 6-22-1 Nishishinjuku, Shinjuku, Tokyo 163-1130, Japan
*3 Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan
*4 Faculty of Pharmacy, Kinki University, 3-4-1 Kowakae, Higashi-Osaka 577-8502, Japan
*5 Department of Biological Chemistry, College of Bioscience and Biotechnology, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan

In order to analyze trigonelline, caffeine, chlorogenic acid, and their related compounds simultaneously, an HPLC method using an InertSustain C18 column and a mobile phase containing octanesulfonate as an ion-pairing reagent under an acidic condition was developed. The optimum mobile phase conditions were determined to be 0.1% phosphoric acid, 4 mM octanesulfonate, and 15% methanol at 35°C. Using the proposed method, trigonelline, nicotinic acid, caffeine, theophylline, chlorogenic acid, and caffeic acid in ten instant coffee samples were analyzed. These analytes except for theophylline were detected in all samples. An increase in the caffeine content in instant coffee samples tended to decrease in both trigonelline and chlorogenic acid contents, and the trigonelline content was found to be correlated well with the chlorogenic acid content (R² = 0.887).

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