title: Potential of IRMS technology for tracing gamma-butyrolactone (GBL).
abstract: Popularity of gamma-hydroxybutyric acid (GHB) is fairly stable among drug users, while the consumption of its chemical precursor, gamma-butyrolactone (GBL), is a growing phenomenon. Although conventional analytical methods allow to detect this substance in various matrices, linking a trace and a source is still a difficult challenge. However, as several synthesis pathways and chemical precursors exist for the production of GBL, its carbon isotopic signature may vary extensively. For that purpose, a method has been developed to determine the carbon isotopes content of GBL by means of gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). The delta(13)C-values of 19 bulk samples purchased worldwide were in the range from -23.1 to -45.8 per thousand (SD<0.3 per thousand). Furthermore, testing on the purification of GBL by distillation has not been found to be consistent with such a large range of delta(13)C-values, which are likely to result from the isotopic composition of the organic precursors used to produce GBL together with the kinetic isotope effect associated with the synthesis routes. Finally, inter- and intra-variability measurements of the delta(13)C-values demonstrated the high potential of IRMS for discriminating between seizures of GBL and for source determination.
authors.affiliation: Swiss Laboratory for Doping Analyses, University Centre of Legal Medecine, Geneva and Lausanne, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Ch. des Croisettes 22, Epalinges, Switzerland.
authors.forename: François
authors.initials: F
authors.lastname: Marclay
authors.forename: Diego
authors.initials: D
authors.lastname: Pazos
authors.forename: Olivier
authors.initials: O
authors.lastname: Delémont
authors.forename: Pierre
authors.initials: P
authors.lastname: Esseiva
authors.forename: Christophe
authors.initials: C
authors.lastname: Saudan