Gamma hydroxybutyric acid – better-known as GHB – is a drug that makes people sleepy and can induce amnesia. That's why it's become a popular "date rape" drug. Unfortunately for law enforcement officials, it can only be detected in the body for a few hours after being ingested. Thanks to new research conducted by Spanish and British scientists, however, there may soon be another way of proving that someone has been given GHB.

In the study, which was led by Míriam Pérez-Trujillo of The Autonomous University of Barcelona, test subjects were given small doses of the drug. Blood and urine samples were then taken from them at regular intervals over the next 30 hours.

When the samples were analyzed using nuclear magnetic resonance spectroscopy, the GHB itself could only be detected in samples taken up to two hours after ingestion. After that point, the drug had been completely metabolized by the body.

That said, a GHB biomarker stuck around for much longer. Known as glycolate, it's produced by the body in response to GHB – and elevated levels of it were found in the volunteers' urine for up to 20 hours after ingestion.

As an added benefit, the testing technique didn't compromise the samples at all. By contrast, testing for GHB itself sometimes results in destruction of the samples, making subsequent tests impossible.

A paper on the research was recently published in the journal Analytical Chemistry.