Determination of N-Acetyl-S-(N-methylcarbamoyl) cysteine in Human Urine by Online Solid Phase Extraction-High Performance Liquid Chromatography

A method was developed for the determination of N-acetyl-S-(N-methylcarbamoyl) cysteine (AMCC) in human urine by online solid-phase extraction (SPE) -high performance liquid chromatography (HPLC). The separation of AMCC from the urine matrix was performed on AmoniPac PA Solid phase Extraction (SPE) column with 5 mmol/L KH2PO4 as the mobile phase by left pump. Then the time was controlled to switch the valve to make only the section of sample containing AMCC transferred into the analytic column-Acclaim PA II C-18 The determination was performed using gradient elution of 0. 1% H3PO4 (containing 5% acetonitrile) and acetonitrile by right pump. The results showed that AMCC present good linear correlation in the range of 1.0-100 mg/L with a correlation coefficient of above 0. 999, the quantitation limit of the method was 0. 2 mg/L (with the sample inject volume =10 mu L), the recoveries of spiked samples were in the range of 82. 9%=85. 9%, and the relative standard deviation (n =6) of retention time and peak area were 0. 2% and 4. 0% respectively. Compared with offline SPE-HPLC, the proposed method was convenient, environmentally friendly, efficient and stable, and feasible for the detection of AMCC in 7 human urine samples.