Determination of gamma-hydroxybutyrate (GHB) in biological specimens by gas chromatography--mass spectrometry.

A simple liquid-liquid extraction procedure for the analysis of gamma-hydroxybutyrate (GHB) in biological fluids without conversion to its lactone, gamma-butyrolactone, is described. Following derivatization to its di-TMS derivative, GHB was detected using gas chromatography-electron impact mass spectrometry. Diethylene glycol was used as the internal standard. The limit of quantitation in 1 mL of blood was 1 mg/L, and a linear response was observed over the concentration range 1 to 100 mg/L. Coefficients of variation for both intra-assay precision and interassay reproducibility ranged between 3.9 and 12.0%. GHB was detected in the blood of a sexual assault victim (3.2 mg/L), in the blood of two driving (DUI) cases (33 and 34 mg/L), and in the blood and urine of two nonfatal GHB-overdose cases (blood 130 and 221 mg/L; urine 1.6 and 2.2 g/L). The observed clinical symptoms ranged from confusion, disorientation, vomiting, and nystagmus to ataxia, sinus bradycardia, unconsciousness, and apnea.