Quantitation of cocaine and its major metabolites in human saliva using gas chromatography-positive chemical ionization-mass spectrometry (GC-PCI-MS).
An analytical method for the simultaneous determination of cocaine (COC) and its major metabolites, ecgonine methyl ester (EME) and benzoylecgonine (BEG), in saliva was developed. The method involves liquid-liquid extraction in Toxitubes A, derivatization with 99:1 (v/v) N,O-bis-trimethylsilyltrifluoroacetamide (BSTFA)/trimethylchlorosilane (TMCS) and gas chromatography-mass spectrometry (GC-MS) determination. The detector response thus obtained is linear over the range 25-1000 ng/mL, with a reproducibility better than 93% and a recovery close to 100% for the three analytes. The limits of detection achieved were 0.9 ng/mL for EME, 2.2 ng/mL for cocaine, and 0.2 ng/mL for BEG, and the limits of quantitation were 3.0 ng/mL for EME, 7.4 ng/mL for cocaine, and 0.8 ng/mL for BEG. The proposed method was applied to 48 saliva samples from cocaine users, 96% of which were positive for the drug and/or its metabolites. Saliva is thus a suitable biological fluid for determining cocaine, EME, and BEG by GC-PCI-MS.
Cámpora
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Institute of Legal Medicine, Forensic Toxicology Service, Faculty of Medicine, University of Santiago de Compostela, Spain.
Bermejo
A M
AM
Tabernero
M J
MJ
Fernández
P
P
D003042:Cocaine / Q000031:analogs & derivatives* / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D009294:Narcotics / Q000032:analysis*; D012463:Saliva / Q000737:chemistry*; D012680:Sensitivity and Specificity; D015813:Substance Abuse Detection / Q000379:methods*
D009294:Narcotics; C005618:benzoylecgonine; D003042:Cocaine; C034524:ecgonine methyl ester