Objective To develop a gas chromatography-tandem mass spectrometry(GC-MS/MS)method for the simultaneous determination of ephedrine and pseudoephedrine in urine.Methods Urine samples containing ephedrine and pseudoephedrine components were extracted with ethyl acetate,centrifuged to collect the supernatant and evaporated to dryness under a nitrogen stream and then derivatized with heptafluorobutyric anhydride 60 μL at 70 ℃ for 30 min,and re-evaporated under nitrogen,and then solubilized with 50 μL of methanol,and then analyzed by GC-MS/MS.Results The method demonstraed excellent linearity for ephedrine(0.05～10 μg/mL,r=0.999 8)and pseudoephedrine(0.02～5 μg/mL,r=0.999 5).Extraction recoveries ranged from 89.4％～95.8％(ephedrine)and 90.3％～93.8％(pseudoephedrine).Limits of detection and quantification of ephedrine and pseudoephedrine were 0.005 μg/mL and 0.01 μg/mL,the intra-day precision and accuracy were less than 5.87％and 9.56％,respectively,and the inter-day precision and accuracy were less than 7.54％and 9.27％,respectively.The stability of ephedrine and pseudoephedrine in urine in 15 d was good under the conditions of room temperature and-20 ℃.Conclusion The GC-MS/MS analytical method for the analysis of ephedrine and pseudoephedrine components in urine established in this study is accurate,stable and sensitive,which can provide data technical support for the forensic toxicological analysis of amphetamine-type drugs or new psychoactive substances in the cathinone group.

Objective To develop a gas chromatography-tandem mass spectrometry(GC-MS/MS)method for the simultaneous determination of ephedrine and pseudoephedrine in urine.Methods Urine samples containing ephedrine and pseudoephedrine components were extracted with ethyl acetate,centrifuged to collect the supernatant and evaporated to dryness under a nitrogen stream and then derivatized with heptafluorobutyric anhydride 60 μL at 70 ℃ for 30 min,and re-evaporated under nitrogen,and then solubilized with 50 μL of methanol,and then analyzed by GC-MS/MS.Results The method demonstraed excellent linearity for ephedrine(0.05～10 μg/mL,r=0.999 8)and pseudoephedrine(0.02～5 μg/mL,r=0.999 5).Extraction recoveries ranged from 89.4％～95.8％(ephedrine)and 90.3％～93.8％(pseudoephedrine).Limits of detection and quantification of ephedrine and pseudoephedrine were 0.005 μg/mL and 0.01 μg/mL,the intra-day precision and accuracy were less than 5.87％and 9.56％,respectively,and the inter-day precision and accuracy were less than 7.54％and 9.27％,respectively.The stability of ephedrine and pseudoephedrine in urine in 15 d was good under the conditions of room temperature and-20 ℃.Conclusion The GC-MS/MS analytical method for the analysis of ephedrine and pseudoephedrine components in urine established in this study is accurate,stable and sensitive,which can provide data technical support for the forensic toxicological analysis of amphetamine-type drugs or new psychoactive substances in the cathinone group.

Objective To establish a method using supramolecular solvent and gas chromatography-tandem mass spectrometry （GC-MS/MS） to analyze 9 benzodiazepines in urines. Methods Urine samples containing 9 benzodiazepines reference substance were subjected to liquid-liquid extractions with supramolecular solvent, which consisted of tetrahydrofuran and 1-hexanol. The solvent layer was evaporated to dryness by stream of nitrogen. The residue was reconstituted with methanol, and GC-MS/MS analysis was performed on it. The way of data collection was multiple reaction monitoring （MRM） mode; internal standard method was employed for quantification. Results In urine samples, when the range of mass concentration was 1-100 ng/mL for diazepam, midazolam, flunitrazepam and clozapine, 5-100 ng/mL for lorazepam and alprazolam, 2-100 ng/mL for nitrazepam and clonazepam, and 0.2-100 ng/mL for estazolam, respectively, good linearities were obtained, correlation coefficients were 0.999 1-0.999 9, the lower limits of the quantifications ranged from 0.2 to 5 ng/mL, the extraction recovery rates were 81.12%-99.52%. The intra-day precision ［relative standard deviation （RSD）］ and accuracy （bias） were lower than 9.86% and 9.51%, respectively; the inter-day precision （RSD） and accuracy （bias） were lower than 8.74% and 9.98%, respectively. Nine drugs in urine samples showed good stability at ambient temperature and -20 ℃ within 15 days. The mass concentrations of alprazolam in urine samples obtained from 8 volunteers who took alprazolam tablets orally within 8-72 h after ingestions ranged from 6.54 to 88.28 ng/mL. Conclusion The supramolecular solvent extraction GC-MS/MS method for analysis of 9 benzodiazepines in urines provided by this study is simple, fast, accurate and sensitive, which can provide technical support for monitoring of poisoning by benzodiazepines for clinical treatment and judicial identification.
Benzodiazepines ; Chromatography, Liquid ; Gas Chromatography-Mass Spectrometry ; Humans ; Solvents ; Tandem Mass Spectrometry