Purpose It is crucial for forensic analysis to differentiate clinical use from illegal abuse. Selegiline (SG) is mainly metabolized to desmethylselegiline (DM-SG), R -(−)-methamphetamine (R-MA) and R-(−)amphetamine (R-AM); while abused methamphetamine and amphetamine mainly contain the S -(+)-form. The aim of this study was to simultaneously determine SG, DM-SG, R / S -MA, and R / S -AM in human oral fluid (OF) and to differentiate clinical use from illegal use. We also aim to apply the present method to the OF samples from authentic cases in forensic toxicology. Methods Liquid–liquid extraction and liquid chromatography-tandem mass spectrometry operating in positive ion multiple-reaction monitoring mode were utilized. The chromatographic system consisted of a Chirobiotic TM V2 column (2.1 mm × 250 mm, 5 μm) and a mobile phase of methanol containing 0.1% (v/v) glacial acetic acid and 0.02% (v/v) ammonium hydroxide. Results and conclusions The calibration curves were linear from 1 to 100 ng/mL, and r > 0.995 for all analytes with imprecisions ≤ 15% and accuracy between 85 and 115%. Extraction recoveries ranged from 46.3 to 104.7% with coefficient of variation (CV) ≤ 10.3% and matrix effects (MEs) ranged from 47.4 to 114.8% with CV ≤ 12.9%. The lower limit of quantification was 0.2 ng/mL for SG and DM-SG and 1.0 ng/mL for S-MA, R-MA, S-AM and R-AM. The present method is simple, rapid (accomplished in 12 min), sensitive, and validated by authentic samples.
Objective: Chiral analysis is a crucial method to differentiate selegiline intake from drug abuse. A dried urine spot (DUS) analytical method based on spotting urine samples (10 μL) onto dried spot collection cards, and followed by air-drying and extraction, was developed and validated for the determination of selegiline, desmethylselegiline, R/S-methamphetamine, and R/S-amphetamine.Methods: Methanol (0.5 mL) was found to be the ideal extraction solvent for target extraction from DUSs under orbital-horizontal stirring on a lateral shaker at 1,450 rpm for 30 min. Determinations were performed by direct electrospray ionization tandem mass spectrometry (ESI-MS/MS) under positive electrospray ionization conditions using multiple reaction monitoring mode. The chromatographic system consisted of a ChirobioticTM V2 column (2.1 × 250 mm, 5 μm) and a mobile phase of methanol containing 0.1% (v/v) glacial acetic acid and 0.02% (v/v) ammonium hydroxide.Results and conclusions: The calibration curves were linear from 50 to 5,000 ng/mL, with r > 0.995 for all analytes, imprecisions ≤ 15% and accuracies between −11.4 and 11.7%. Extraction recoveries ranged from 48.6 to 105.4% with coefficients of variation (CV) ≤ 13.7%, and matrix effects ranged from 45.4 to 104.1% with CV ≤ 10.3%. The lower limit of quantification was 50 ng/mL for each analyte. The present method is simple, rapid (accomplished in 12 min), sensitive, and validated by a pharmacokinetic study in human urine collected after a single oral administration of SG.