Detection of exogenous GHB in blood by gas chromatography-combustion-isotope ratio mass spectrometry: implications in postmortem toxicology.
Because GHB (gamma-hydroxybutyrate) is present in both blood and urine of the general population, toxicologists must be able to discriminate between endogenous levels and a concentration resulting from exposure. In this paper, we propose a procedure for the detection of exogenous GHB in blood by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). Following liquid-liquid and solid-phase extractions, GHB is derivatized to GHB di-TMS before analysis by GC-C-IRMS. Significant differences in the carbon isotopic ratio (delta(13)C-values > 13.5 per thousand) were found between endogenous and synthetic GHB. Indeed, for postmortem blood samples with different GHB concentrations (range: 13.8-86.3 mg/L), we have obtained GHB delta(13)C-values ranging from -20.6 to -24.7 per thousand, whereas delta(13)C-values for the GHB from police seizure were in the range -38.2 to -50.2 per thousand. In contrast to the use of cut-off concentrations for positive postmortem blood GHB concentrations, this method should provide an unambiguous indication of the drug origin.
Saudan
Christophe
C
Laboratoire Suisse d'Analyse du Dopage, Institut Universitaire de Médecine Légale, Rue du Bugnon 21, 1005 Lausanne, Switzerland. csaudan@hospvd.ch
Augsburger
Marc
M
Kintz
Pascal
P
Saugy
Martial
M
Mangin
Patrice
P
D002247:Carbon Isotopes; D005554:Forensic Medicine / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D012978:Sodium Oxybate / Q000097:blood*; D015813:Substance Abuse Detection / Q000379:methods*
D002247:Carbon Isotopes; D012978:Sodium Oxybate