Determination of nicotine, anabasine, and cotinine in urine and saliva samples using single-drop microextraction

A simple, sensitive, and inexpensive singe-drop microextraction (SDME) followed by gas chromatography and flame-ionization detection (GC-FID) was developed for determination of nicotine, anabasine, and cotinine in human urine and saliva samples. The target compounds were extracted from alkaline aqueous sample solution into an organic acceptor drop suspended on the tip of a 25-μL GC microsyringe in the aqueous sample solution. This microsyringe was also used for direct injection after extraction. Under optimized experimental conditions, calibration plots were found to be linear in the range of 0.5–25.0, 0.5–65.0, and 0.5–45.0 mg L−1 for nicotine, anabasines and cotinine, respectively. The method detection limit values were in the range of 0.33–0.45 mg L−1. Intra-day and inter-day precisions for peak area ratios were in the range of 1.3–9.2% and 2.0–7.0%, respectively. The proposed procedure was successfully applied to the determination of analytes in spiked urine and saliva samples with satisfactory results. The mean relative recoveries of spiked water samples ranged over 71.2–111.0%, with relative standard deviations varying from 2.3% to 10.0%.