Washington, August 8 : Fingerprints would now be able to provide clues to more than just identity, with the use of a new technology that detects trace amounts of explosives, drugs or other materials left behind in the prints.
The new technology, developed by a team led by R. Graham Cooks from Purdue University in the US, uses a tool that reads and provides an image of a fingerprint's chemical signature.
The technology can be used to determine what a person recently handled.
"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," said Cooks.
"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," he added.
According to Demian R. Ifa, a Purdue postdoctoral researcher, the technology also can easily uncover fingerprints buried beneath others.
"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," said Ifa.
"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," he added.
Researchers examined fingerprints in situ or lifted them from different surfaces such as glass, metal and plastic using common clear plastic tape. They then analyzed them with a mass spectrometry technique developed in Cooks' lab.
Mass spectrometry works by first turning molecules into ions, or electrically charged versions of themselves, so their masses can be analyzed.
Conventional mass spectrometry requires chemical separations, manipulations of samples and containment in a vacuum chamber for ionization and analysis.
Cooks' technology performs the ionization step in the air or directly on surfaces outside of the mass spectrometer's vacuum chamber, making the process much faster and more portable.
Researchers placed a section of tape containing a lifted fingerprint on a moving stage in front of the spectrometer.
The spectrometer then sprayed small sections of the sample with the charged water droplets, obtaining data for each section and combining the data sets to create an analysis of the sample as a whole.
Software was used to map the information and create an image of the fingerprint from the distribution and intensity of selected ions.
The new technology can also distinguish between overlapping fingerprints left by different individuals - a difficult task for current optical forensic methods.