Determination of N-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC) in urine by high-performance liquid chromatography combined with mass spectrometry

A simple, sensitive and specific method for the quantification of N-acetyl-S-(N-methylcarbamoyl)-cysteine (AMCC) in urines of the general population and of exposed workers has been developed. Samples were first diluted with phosphate buffer followed by purification by solid-phase extraction (SPE) with SAX columns prior to analysis by liquid chromatography/mass spectrometry (LC/MS). An external standard was used for the quantification together with selected ion monitoring of m/z 219, [M-H](-). The linear calibration curve showed a good correlation (r(2) = 0.98, p < 0.001) between 0.1-110 mg/L of AMCC, and the detection limit was calculated to be 2 mug/L. The within-day and between-day precision, calculated for exposed workers and general population AMCC levels in urine samples, were determined as 1.2 and 3.6%, respectively (as relative standard deviation (RSD)). Copyright (C) 2004 John Wiley Sons, Ltd.