Determination of the illicit drug gamma-hydroxybutyrate (GHB) in human saliva and beverages by 1H NMR analysis

High resolution H-1 NMR spectroscopy has been employed to investigate the detection and quantification of the illicit 'date-rape' drug gamma-hydroxybutyrate (GHB) in both human saliva and a commonly-consumed low-alcohol beer product. Data acquired revealed that this multicomponent analytical technique provided unequivocal evidence for the detection of this agent by this technique in both of these matrices, i.e., all three of its resonances [those ascribable to the alpha-CH2 (t, delta = 2.25 ppm), beta-CH2 (tt, delta = 1.81 ppm) and gamma-CH2 (t, delta = 3.61 ppm) group protons] were present in spectra acquired on human saliva, and two of these (the alpha- and beta-CH2 group signals) in the beverage product examined, the latter observation attributable to overlap of the gamma-CH2 H-1 resonance with those of carbohydrates. Since good linear calibration relationships between the intensities of each of the NMR-visible signals and added GHB concentration ( the former normalised to that of an external 3-trimethylsilyl [2,2,3,3-(2)H4]-propionate standard present in a coaxial NMR tube insert) were observed, this illicit drug is also readily quantifiable in such multicomponent samples. Our data demonstrate the advantages offered by this technique when applied to the analysis of illicit drugs in multicomponent sample matrices such as human biofluids and beverage products.