Detection of GHB at low levels in non-spiked beverages using solid phase extraction and gas chromatography-mass spectrometry

Gamma-hydroxybutyric acid (GHB) is an endogenous neurotransmitter, a drug and a drug of abuse. It has been frequently implicated in instances of drug-facilitated crimes (DFSA) when drugs or pharmaceuticals are covertly administered to victims to render them nearly or fully unconscious before robbery or sexual assaults. In order to assist in the interpretation of cases where beverages have been offered to victims, it is important to distinguish between spiked and endogenous presence of GHB with a specific and sensitive method. The method is based on solid phase extraction with an ionic exchange cartridge and gas chromatography mass spectrometry detection in multiple ion monitoring. The method is linear in the 20-1000 ng/mL range, with a lowest limit of quantification of 6.7 ng/mL and a limit of detection of 4.5 ng/mL. The validated method allowed to evidence the presence of non-spiked GHB in commercially available, alcoholic and nonalcoholic drinks. For the first time, GHB was detected in tonic water and lemon tonic water (130-180 ng/mL), rum (100-150 ng/mL), vodka (160-190 ng/mL), tequila (210-270 ng/mL) and fruit juice (380-500 ng/mL) while its presence was confirmed in beer (330-430 ng/mL) and in red (9300-12,000 ng/mL) and white wine (2500-3200 ng/mL). The detection of endogenous GHB at low levels in both alcoholic and nonalcoholic commercially available beverages suggests that there may be interpretative issues when investigating drug-facilitated crimes.