Research published today in the journal Analyst has demonstrated a new, noninvasive test that can detect cocaine use through a simple fingerprint. For the first time, this new fingerprint method can determine whether cocaine has been ingested, rather than just touched.
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 have actually taken the drug.
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. The researchers then 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.
It is anticipated that this technology could see the introduction of portable drug tests for law enforcement agencies to use within the next decade.