Microwave-assisted silylation followed by gas chromatography/mass spectrometry for simultaneous quantification of nicotine and its four metabolites in urine

In this work, for the first time, microwave-assisted silylation (MAS) followed by gas chromatography-mass spectrometry (GC-MS) was developed for the fast analysis of nicotine and its four metabolites in human urine. MAS conditions and the method's validation were studied. It was found that the derivatization time of 10 min with 200 W microwave power are the best conditions to derive nicotine's metabolites in urine samples. The calibration curve shows good linearity in 0.02–20.00 mg L−1 for nicotine (R2 = 0.9987), cotinine(R2 = 0.9959), and 3-hydroxycotinine (R2 = 0.9974) and 0.02–0.80 mg L−1 for nornicotine(R2 = 0.9998) and norcotinine (R2 = 0.9986), respectively. The RSD values for them are 7.39%, 1.94%, 4.62%, 6.37% and 2.4%, respectively, indicating good reproducibility. The proposed method was successfully applied to the determination of nicotine and its four metabolites in urine from active smokers as well as non-smokers susceptible to passive smoking.