Advertisement

GHB, y-hydroxybutyric acid, is the most commonly used date rape drug, dropped into someone’s drink to incapacitate a victim before a sexual attack. One challenge for forensic chemists is that the drug is quickly metabolized, and is generally undetectable in urine and blood beyond four hours—a crucial timeframe which passes quickly in the wake of a crime.

But a new study utilizing advanced nuclear magnetic resonance (NMR) spectroscopy has found metabolites of the drug in urine and serum even more than 24 hours after ingestion—potentially revolutionizing date rape investigations of the future, reports an international team in the American Chemical Society journal Analytical Chemistry.

“Unlike current procedures for the analyses of consumed GHB (mostly based on GC/MS and LC-MS), NMR spectroscopy allowed the quick monitoring of exogenous GHB within the almost intact bodily fluid,” they write.

The gas chromatography and liquid chromatography analyses have only provided accurate estimations of GHB dosing up to four hours in urine and blood, since the body breaks it down and expels the excess to ambient levels quickly (GHB is also a naturally occurring metabolite of an inhibitory neurotransmitter known as GABA).

The team of scientists, led by Miriam Perez-Trujillo at the Universitat Autonoma de Barcelona, dosed 12 healthy volunteers with the drug, and then tested their urine and blood for traces of the drug and its metabolites.

The sampling continued at intervals from 10 minutes before the drug was administered, to up to 30 hours for urine and 13 hours for blood.

The NMR spectroscopy identified GHB and succinate for a number of hours before they disappeared. But another chemical, glycolate, was a consistent clue for more than a day after the ingestion.

“As shown, while GHB and succinate concentrations dropped rapidly to an endogenous level (at the time point of 6 hours), glycolate concentration decreased much slower, and even after 24 hours, a small difference can be observed,” they report. “According to these results, glycolate, with a longer detection time window than exogenous GHB, could be an interesting candidate for a surrogate biomarker.”

Previous analyses of date rape investigations have concluded that gas and liquid chromatography were the standards for chemists, as a United Nations report concluded in 2011. However, the NMR method of detecting trace metabolites could replace those standards, the authors conclude. 

Advertisement
Advertisement