A Rapid and Simultaneous Quantification Method for Nicotine and Cotinine in Serum by Gas-Liquid Chromatography with a Flame Thermionic Detector

Abstract

A simple and sensitive method was developed for simultaneous determinations of blood nicotine and its major metabolite, cotinine. The two-step extraction method using 0.5 ml of serum was performed without evaporation, and quantification was carried out by gas chromatography with a flame thermionic detector. The reproducibility of this method was good, and the recovery was about 100% (99-101%). Linearity was observed in the range of 5-40 ng/ml for nicotine and 50-400 ng/ml for cotinine The detection limit, expressed as the concentration in the test sample, was about 0.1 ng/ml for nicotine and 1 ng/ml for cotinine. Blood nicotine and cotinine levels were determined by this method in smokers, and their pharmacokinetics were evaluated. The half-life of blood nicotine using a 2-compartment model was 9.2 min in the α phase and 67.6 min in the β phase, and that of cotinine using a 1-compartment model was 30.7 h.