Quantitation of mercapturic acids from acrylamide and glycidamide in human urine using a column switching tool with two trap columns and electrospray tandem mass spectrometry

A sensitive and specific electrospray tandem mass spectrometry method using a column switching unit with two trap columns was established to quantify the mercapturates (MAs) of acrylamide (AA) and glycidamide (GA) in human urine. A specially endcapped material was applied for trapping the hydrophilic MAs and a pre-trap column was used to remove lipophilic compounds from the directly injected urine to protect the trap column. The limits of quantitation for AA–MA and GA–MA in urine were 0.5 μg/L and 1 μg/L, respectively. Urine was spiked with deuterated internal standards and injected directly into LC–MS/MS. Urine of smokers (n = 13) revealed the highest concentrations of AA–MA and GA–MA in the range of 61–706 μg/L and 5–54 μg/L, respectively. Lower levels for AA–MA (14–102 μg/L) and GA–MA (1–11 μg/L) were detected in non-smokers (n = 13).