Occurrence of D-amino acids in food : Detection by capillary gas chromatography and by reversed-phase high-performance liquid chromatography with L-phenylalaninamides as chiral selectors

Abstract

The presence of D-amino acids was investigated in dairy products, in raw ham and in roasted coffee. The analysis was carried on by capillary gas chromatography, using a very stable tetraamidic selector derived from L-phenylalanine, which allowed the detection of D-alanine, D-aspartic acid, D-glutamic acid and other D-amino acids. Moreover, D-glutamic acid and D-alanine were detected also by reversed-phase high-performance liquid chromatography, using L-phenylalaninamide and copper(II) acetate as chiral additives to the eluent. The presence of D-amino acids may be ascribed to thermal racemization or to microbial activity.