Trigonellin in Bohnenkaffee

Determination of trigonelline in several green and roasted coffees by thin-layer (TLC) and high-performance liquid chromatography (HPLC) were compared. Using TLC, two methods of detection were also compared. In addition, caffeine could be determined using HPLC. The determinations were each made with several variations of extraction and clean-up. Recoveries, variation coefficients and detection limits are listed. The most suitable method was HPLC in connection with hot water extraction. Only water is required as the mobile phase. The values for precision are in most cases better than (trigonelline) or similar to (caffeine) those reported in the literature. The determination of trigonelline by TLC, followed by extraction and photometry, is possible with a similar precision, but the simultaneous determination of caffeine was not tested.