Researchers develop new method to detect date rape drug in drinks

Smartphone technology could be used to detect the presence of date rape drugs in drinks, researchers at UWE Bristol have found.

Academics have discovered that the presence of illegal substance gamma-hydroxybutyrate (GHB) can be identified by taking a photograph of a drink and using a simple free app to check its colour. Following the addition of a simple chemical reagent, if the app detects a particular concentration of purple, it indicates the liquid is highly likely to contain the drug.

GHB, more commonly known as ‘Liquid Ecstasy’, is a Class C drug in the UK and prohibited for sale as a supplement in the USA. Due to its strong sedative and amnesic effects, it has been linked to drug-facilitated sexual assault cases, poisoning, and overdose.

As GHB has restricted availability, users are switching to its alternative gamma-butyrolactone (GBL), which is legal to purchase in the UK but has the same effects as GHB when consumed orally.

Researcher Dr Kevin Honeychurch, a Senior Lecturer in Forensic Chemistry, said GHB has previously been challenging to detect using spot testing, liquid chromatography, biosensing and gas chromatographic methods. Detection generally requires a well-equipped laboratory and trained staff.

Working with UWE Bristol student Anselmo Procida, Dr Honeychurch has developed an alternative method which involves adding readily available chemicals (hydroxylamine and ferric chloride) to a drink and then checking the liquid with a free smartphone app to measure the level of purple it produces.

Researchers believe the technology could be developed for point-of-use or care use, to detect the presence of the drug without the need for time-consuming and expensive laboratory tests.

“There is a growing need for methods capable of determining GBL in complex samples such as beverages,” said Dr Honeychurch. “There has recently been a rise in drink spiking incidents reported in the UK, and high-profile cases relating to the misuse of GHB have appeared in the media.

“This application uses a technology available to virtually everybody, outside of a laboratory setting and is operable without professional training or complex laboratory instrumentation.”

A downloadable free app available from the Apple App Store (Color Picker and Helper, version 1.1.6) was used for the research. The app was used to extract the numerical values of the Red, Green, and Blue (RGB) colour components of the liquid being tested. Using these values, it was possible to determine the concentration of the GHB present in fortified lager samples.

“The huge advantage of this approach is that it rules out the need for expensive pieces of lab equipment to conduct the tests,” said Anselmo Procida, who is studying forensic science at UWE Bristol.

“Tests could be done out in the field, at the point of need, as smartphones are devices that most people carry with them and are always available. Because it is a simple test you can conduct on the drink yourself, it doesn’t require technical knowledge.”

The findings of the research were published in a paper: Procida, A., & Honeychurch, K. C. (2022). Smartphone-based colorimetric determination of gamma-butyrolactone and gamma-hydroxybutyrate in alcoholic beverage samples. Journal of Forensic Sciences.