High-performance liquid chromatographic determination of four biogenic amines in chocolate

Abstract

Some biogenic amines occur in a wide variety of foods including cheese, fish, bakery products, milk products and chocolate. This study was undertaken to analyse and quantify four of the biogenic amines thought to occur in chocolate. Tyramine, tryptamine, 2-phenylethylamine and serotonin (5-hydroxytryptamine) were chosen as the amines of interest. Two high-performance liquid chromatographic (HPLC) systems were used for the final analysis of amine extracts. Both systems employed dual detection, with the first using ultraviolet absorbance at 254 nm and the formation of a post-column o-phthaldehyde derivative. The second method used ultraviolet absorbance at 254 nm and the natural fluorescence of the four amines. Thin-layer chromatography (TLC) was performed on all of the extracts to provide further confirmation. All four amines were detected and quantified at varying levels in extracts of several kinds of chocolate and chocolate liquors.