Determination of the major mercapturic acids of acrylamide and glycidamide in human urine by LC-ESI-MS/MS

Abstract

We developed a LC-MS/MS method for the quantitative determination of the mercapturic acid (MA) metabolites of acrylamide (AA) AAMA and of its oxidative metabolite glycidamide (GA) GAMA in urine samples from the general population. The method requires 4 mL of urine which is solid phase extracted prior to LC-MS/MS analysis. The metabolites are detected by ESI-tandem mass spectrometry in negative ionisation mode and quantified by isotope dilution. Detection limits ranged down to 1.5 microg/L urine for both AAMA and GAMA. The imprecision expressed as R.S.D. lay between 2% and 6% for both analytes (intra- and inter-assay). First results on a small group of 29 persons out of the general population ranged from 5 to 338 microg/L AAMA and <LOD to 45 microg/L GAMA in urine. Only in one urine sample GAMA could not be detected. With this sensitive, reliable and rapid method we can determine the internal exposure of the general population to acrylamide in terms of the mercapturic acids. Especially the determination of GAMA is of great toxicological importance because GA is the ultimate carcinogenic agent in AA metabolism. The method therefore provides better insight into the metabolism of acrylamide in humans and furthermore supports risk assessments.