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Published: 15 May 2015

New test detects drug use from a single fingerprint

Research led by Surrey has demonstrated a new, non-invasive test that can detect cocaine use through a simple fingerprint. For the first time, this new method can determine whether cocaine has been ingested, rather than just touched.

The team also included the Netherlands Forensic Institute (NL), the National Physical Laboratory (UK), King’s College London (UK) and Sheffield Hallam University (UK). The Researchers used different types of an analytical chemistry technique known as mass spectrometry to analyse the fingerprints of patients attending drug treatment services.

They tested these prints against more commonly used saliva samples to determine whether the two tests correlated. While previous fingerprint tests have employed similar methods, they have only been able to show whether a person had touched cocaine, and not whether they had actually taken the drug.

Dr Melanie Bailey, from the University’s Department of Chemistry, said:  “When someone has taken cocaine, they excrete traces of benzoylecgonine and methylecgonine as they metabolise the drug, and these chemical indicators are present in fingerprint residue.

“We sprayed a beam of solvent onto the fingerprint slide (a technique known as Desorption Electrospray Ionisation, or DESI) to determine if these substances were present. DESI has been used for a number of forensic applications, but no other studies have shown it to demonstrate drug use.”

Researchers believe that the applications for this test could be far-reaching. Drug testing is used routinely by probation services, prisons, courts and other law enforcement agencies. However, traditional testing methods have limitations. For example, blood testing requires trained staff and there are privacy concerns about urine testing. Where bodily fluids are tested, there can be biological hazards and often a requirement for particular storage and disposal methods. Often these tests also require analysis off-site.

“The beauty of this method is that, not only is it non-invasive and more hygienic than testing blood or saliva, it can’t be faked,” added Dr Bailey. “Companies are already working on miniaturised mass spectrometers, and, in the future, portable fingerprint drugs tests could be used. This will help to protect the public and indeed provide a much safer test for drug users.”

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