DEVELOPMENT AND VALIDATION OF SENSITIVE METHOD FOR DETERMINATION OF SERUM COTININE IN SMOKERS AND NONSMOKERS BY LIQUID-CHROMATOGRAPHY ATMOSPHERIC-PRESSURE IONIZATION TANDEM MASS-SPECTROMETRY

We describe a sensitive and specific method for measuring cotinine in serum by HPLC coupled to an atmospheric pressure chemical ionization t andem mass spectrometer. This method can analyze 100 samples/day on a routine basis, and its limit of detection of 50 ng/L makes it applicab le to the analysis of samples from nonsmokers potentially exposed to e nvironmental tobacco smoke. Analytical accuracy has been demonstrated from the analysis of NIST cotinine standards and from comparative anal yses by both the current method and gas chromatography/high-resolution mass spectrometry. Precision has been examined through the repetitive analysis of a series of bench and blind QC materials. This method has been applied to the analysis of cotinine ia serum samples collected a s part of the Third National Health and Nutrition Examination Survey ( NHANES III).