Fingerprints could be used to detect traces of drugs or explosives in one of the most important advances in the technology for a long time.

Police now have the power to examine the traces of cannabis, cocaine and other drugs, or explosives, in a fingerprint itself.

The recently technique uncovers, in extraordinary detail, the chemical compounds that composition the print and could also detect medical uses, as little traces of chemicals at our fingertips may signal the presence of a disease or an sickness.

This technique can also be applied directly on a fingerprint, right where it’s found, without the require to lift the print off and carry it to a lab for analysis.

Dr Demian Ifa, Prof Graham Cooks at Purdue University in West Lafayette, and colleagues reports in the journal Science how they applied a process called desorption electrospray ionization, or DESI, which requires spraying a solvent onto a fingerprinted surface and then examining the droplets that scatter off the print with a technique called mass spectroscopy.

The method provides a “chemical image” of the fingerprint with higher resolution than other methods, and can examine as little as a billionth of a gram of material, said Prof Cooks.

“The classic example of a fingerprint is an ink imprint showing the unique swirls and loops used for identification, but fingerprints also leave behind a unique distribution of molecular compounds,” Prof Cooks said. “Some of the residues left behind are from naturally occurring compounds in the skin and some are from other surfaces or materials a person has touched.”

In that way, the researchers can detect minute traces of compounds - marked as dots on the print - that were on the fingertips of the person who left the print.

This method can pick up small measures of drugs like cocaine or THC, the active element from marijuana, as well as chemical compound from explosives.

Researchers may besides find this method useful for identifying metabolites or other chemical compound in fingertip secretions, whose presence could signal additional processes occurring inside the body.

The team is also analysing if it can be applied as an alternative to blood and urine tests for athletes, said Prof Cooks.

(A) DESI image of cocaine on a print blotted on glass (B) Computer print from DESI image (C) Ink print blotted on paper, (D) Computer print from optical image .

The image could also be analysed with basic fingerprint imaging software to try to distinguish that person and help distinguish overlapping prints.”Because the distribution of compounds found in each fingerprint can be unique, we also can use this technology to pull one fingerprint out from beneath layers of other fingerprints,” Dr Ifa said.

“By looking for compounds we know to be present in a certain fingerprint, we can separate it from the others and obtain a crystal clear image of that fingerprint. The image could then be used with fingerprint recognition software to identify an individual.”

Original Article: New fingerprint method can spot drugs or explosives

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