Researchers have developed a new fingerprint analysis technique that can detect whether a person has taken cocaine. The study, published in the journal Analyst, suggests fingerprints provide a ‘non-invasive’ and ‘hygienic’ alternative to current testing methods.
Researchers from the University of Surrey used an analytical chemistry technique called mass spectrometry to detect the chemicals that cocaine users release when the drug is broken down in the body. These chemicals, called benzoylecgonine and methylecgonine, are found in fingerprint residue. By analyzing these fingerprints, researchers were able to test whether cocaine had been ingested, not just touched.
"For our part of the investigations, we sprayed a beam of solvent onto the fingerprint slide (a technique known as Desorption Electrospray Ionization, 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,” lead author Dr. Melanie Bailey from the University of Surrey said in a statement.
Researchers tested the fingerprints from patients attending drug treatment services against the more traditional method of analyzing saliva samples. The study showed the test could be as accurate as conventional methods.
"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," said Bailey. "By the very nature of the test, the identity of the subject is captured within the fingerprint ridge detail itself."
Fingerprints can overcome the particular limitations associated with blood and urine testing, researchers suggest. Blood testing can require trained staff, and urine testing raises privacy concerns, and both samples have to be treated as biological hazards.
Bailey suggests a range of uses for fingerprint testing, including drug tests for law enforcement.
While the study points to the possibility of the test becoming portable, Bailey tells the BBC that the mass spectrometer is currently “the same size as a washing machine” and the one used in the study is not cheap. Researchers hope with the development of smaller and cheaper mass spectrometers, the test could become portable and widely available.
"We are only bound by the size of the current technology. Companies are already working on miniaturized mass spectrometers, and in the future portable fingerprint drugs tests could be deployed. This will help to protect the public and indeed provide a much safer test for drug users," said Dr. Bailey.
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