Simultaneous and sensitive measurement of anabasine, nicotine, and nicotine metabolites in human urine by liquid chromatography-tandem mass spectrometry

Background: Determination of nicotine metabolism/ pharmacokinetics provides a useful tool for, estimating uptake of nicotine and tobacco-related toxicants, for understanding the pharmacologic effects of nicotine and nicotine addiction, and for optimizing nicotine dependency treatment. Methods: We developed a sensitive method for analysis of nicotine and five major nicotine metabolites, including cotinine, trans-3'-hydroxycotinine, nicotine-N'-oxide, cotinine-N-oxide, and nornicotine, in human urine by liquid chromatography coupled with a TSQ Quantum triple quadrupole tandem mass spectrometer (LC/ MS/MS). Urine samples to which deuterium-labeled internal standards had been added were extracted with a simple solid-phase extraction procedure. Anabasine, a minor tobacco alkaloid, was also included. Results: The quantification limits of the method were 0.1-0.2 mug/L, except for nicotine (1 mug/L). Cotinine-Noxide, trans-3'-hydroxycotinine, nicotine, and anabasine in urine were almost completely recovered by the solidphase extraction, whereas the mean extraction recoveries of nicotine-N'-oxide, cotinine, and nornicotine were 51.4%, 78.6%, and 78.8%, respectively. This procedure provided a linearity of three to four orders of magnitude for the target analytes: 0.2-400 mug/L for nicotne-N'- oxide, cotinine-N-oxide, and anabasine; 0.2-4000 mug/L for cotinine, nornicotine, and trans-3'-hydroxycotinine; and 1.0-4000 mug/L for nicotine. The overall interday method imprecision and recovery were 2.5-18% and 92-109%, respectively. Conclusions: This sensitive LC/MS/MS procedure can be used to determine nicotine metabolism profiles of smokers, people during nicotine replacement therapy, and passively exposed nonsmokers. This method avoids the need for a time-consuming and labor-intensive sample enrichment step and thus allows for high-throughput sample preparation and automation. (C) 2004 American Association for Clinical Chemistry.