Fast and sample cleanup-free measurement of nicotine and cotinine by stable isotope dilution ultra-performance liquid chromatography-tandem mass spectrometry

► Highly specific UPLC-MS/MS method to measure nicotine and cotinine. ► Sample preparation by simple dilution with internal standard mixture. ► Very fast measurement of nicotine and cotinine in human urine. ► Comparison of cotinine results measured by the new UPLC-MS/MS assay with the nicotine metabolites obtained by a nicotine metabolite chemiluminescent immunoassay. ► Determination of the smoking status of smokers using cotinine level as indicator.