title: Quantitative analysis of the endogenous GHB level in the hair of the Chinese population using GC/MS/MS.
abstract: Endogenous production complicates interpretation when gamma-hydroxybutyrate (GHB) is measured in hair for forensic purposes. A method capable of quantifying the endogenous concentration of GHB in human head hair was developed and validated using GC/MS/MS. Hair was digested under alkaline conditions (1 mol/L NaOH, 90 °C 10 min), and GHB-d6 was used as an internal standard. Before derivatization with BSTFA and ethyl acetate, a liquid-liquid extraction with ethyl acetate under acidic conditions was performed. GHB-TMS derivatives were detected using GC/MS/MS in the multiple-reaction monitoring mode. This method exhibited good linearity (y = 0.018x + 0.038, R(2) = 0.9998), and the limit of detection was 0.02 ng/mg. The extraction recoveries were more than 60%, and the inter-day and intra-day relative standard deviations (RSD) were less than 15%. This method has been applied for the analysis of the endogenous GHB in hair samples from 66 drug-free Chinese donors. The mean measured concentration for 0-3 cm hair was 1.93 ± 1.40 ng/mg (n = 66), and extreme values were in the range of 0.28-4.91 ng/mg. The mean male endogenous GHB level was 2.95 ng/mg (0.92-4.91 ng/mg, n = 35), while the mean female level was 0.77 ng/mg (0.28-1.95 ng/mg, n = 31). This method was applied to a forensic case for the determination of GHB in hair samples but it is hard to make a reasonable "cut off" in hair. The solution is to use each subject as his own control.
authors.affiliation: Department of Forensic Toxicology, Institute of Forensic Sciences, Ministry of Justice, Shanghai Key Laboratory of Forensic Medicine, Guangfu Xi Road 1347, Shanghai 200063, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Shi
authors.affiliation: Department of Forensic Toxicology, Institute of Forensic Sciences, Ministry of Justice, Shanghai Key Laboratory of Forensic Medicine, Guangfu Xi Road 1347, Shanghai 200063, PR China.
authors.forename: Xiaopei
authors.initials: X
authors.lastname: Cui
authors.affiliation: Department of Forensic Toxicology, Institute of Forensic Sciences, Ministry of Justice, Shanghai Key Laboratory of Forensic Medicine, Guangfu Xi Road 1347, Shanghai 200063, PR China. Electronic address: minshensfjd@hotmail.com.
authors.forename: Min
authors.initials: M
authors.lastname: Shen
authors.affiliation: Department of Forensic Toxicology, Institute of Forensic Sciences, Ministry of Justice, Shanghai Key Laboratory of Forensic Medicine, Guangfu Xi Road 1347, Shanghai 200063, PR China. Electronic address: xiangping2630@163.com.
authors.forename: Ping
authors.initials: P
authors.lastname: Xiang
mesh_terms: D044466:Asian People; D002681:China; D002849:Chromatography, Gas; D005260:Female; D053593:Forensic Toxicology; D006197:Hair / Q000378:metabolism*; D006801:Humans; D057230:Limit of Detection; D016014:Linear Models; D008297:Male; D012978:Sodium Oxybate / Q000378:metabolism*; D053719:Tandem Mass Spectrometry
chemical_list: D012978:Sodium Oxybate
keywords: Endogenous; Forensic toxicology; GHB; Gas chromatography-tandem mass spectrometry; Hair