Automated solid-phase extraction and liquid chromatography tandem mass spectrometry determination of N-methyl-2-pyrrolidone and its metabolites in urine and plasma

A method for the simultaneous determination of N-methyl-2-pyrrolidone (NMP) and its metabolites 5-hydroxyl-N-pyrrolidone (5HNMP), N-methylsuccinimide (MSI) and 2-hydroxy-N-methylsuccinimide (2HMSI) in plasma and urine has been developed. Samples were purified by SPE using an ASPEC XL4. Analysis was performed using LC-MS equipped with an APCI interface. The analysis provided linear responses in the range of 0.125-12 mu g mL(-1) for all of the analytes and up to 150 mu g mL(-1) for 5HNMP and 2HMS1. The within day precision was in the range of 0.9-19.1% for plasma samples and 1.9-10.4% for urine samples whereas the between day precisions were 4.5-11.9% and 1.2-17.5%, respectively. The method was deemed to be suitable for monitoring the levels of NMP and its metabolites in the plasma and urine of occupationally exposed persons