Forensic technology could trace drugs to point of manufacture

Researchers at Strathclyde University are focusing on a class of substances called cathinones, often sold and labelled as bath salts, plant food and incense.

They mimic the effects of illegal drugs such as amphetamine, cocaine and ecstasy, but have subtly different molecular structures.

This makes them difficult to identify based on established techniques such as nuclear magnetic resonance (NMR), gas chromatography and ultraviolet and infrared detection.

Over the past couple of years, the Strathclyde team has built up a catalogue of pure reference standards of designer drugs based on variations of mephedrone. But, as project lead Dr Oliver Sutcliffe of Strathclyde explained to The Engineer, this doesn’t address the route of the problem.

‘With the drugs trade you are always playing catch-up, because as soon as you ban a substance, three more will spring up in its place.

‘A lot of these clandestine laboratories are just handle turning — all they’re are doing is saying “let’s just change this part of the molecule”. They don’t care about the activity; they’re not doing a drug-discovery process here.’

Based on this, the researchers realised that they might be able to use a relatively new technique called isotope ratio mass spectrometry (IRMS) to work backwards and trace the substances to their starting materials. This is because IRMS measures the relative amounts of an element’s different forms, which are transferred like a ‘fingerprint’ through the synthesis of the drug, as Sutcliffe explained.

‘Basically, every molecule has an isotopic ratio associated with it and it’s determined by the starting material that you prepare that molecule from and the method that you use to synthesise it.’

The researchers have performed preliminary tests in the lab, where they made mephedrone from different batches and were subsequently able to differentiate them retrospectively.

Nevertheless, Sutcliffe cautions: ‘This is not the golden bullet; it will not tell you that that [substance] has come from lab X in country Y — at the moment.’