ISOLATION BY SOLID-PHASE EXTRACTION AND LIQUID-CHROMATOGRAPHIC DETERMINATION OF MUTAGENIC AMINES IN BEEF EXTRACTS

A solid-phase extraction method was successfully optimized for the iso lation and preconcentration of five mutagenic amines, 3-amino-1,4-dime thyl-5H-pyrido[4,3-b]indole, 3-amino-1-methyl-5H-pyrido[4,3-b]indole, 2-amino-9H-pyrido[2,3-b]indole, 2-amino-3-methyl-9H-pyrido[2,3-b]indol e and 2-amino-1-methyl-6-phenyl-imidazo[4,5-b]pyridine, and two co-mut agens, 1-methyl-9H-pyrido[4,3-b]indole and 9H-pyrido[4,3-b]indole. Cou pling of diatomaceous earth, propylsulphonyl silica gel, and octadecyl silane cartridges was used to separate selectively the imidazopyridine and indolpyridine derivatives from those of quinoxaline and quinoline . A method based on this sample preparation was applied to the determi nation of twelve heterocyclic amines and related substances in a comme rcial beef extract using HPLC with electrochemical and fluorescence de tection. Good recovery values were obtained, ranging between 55 and 99 %. The co-mutagens 1-methyl-9H-pyrido[4,3-b]indole (harman) and 9H-pyr ido[4,3-b]indole (norharman) were found in the beef extract at levels of 110 and 53 ng g(-1) respectively, and 3-amino-1-methyl-5H-pyrido[4, 3-b]indole (Trp-P-2) and 2-amino-9H-pyrido[2,3-b]indole (A alpha C) we re tentatively identified.