August 7, 2007 Imagine if a single fingerprint could reveal the diet, race and sex of a suspected criminal. As far fetched as the proposition sounds, it might soon become a reality according to new research published in the August edition of the journal Analytical Chemistry. The new technique collects fingerprints along with their chemical residue - containing a few millionths of a gram of fluid - and keeps it intact for future reference. These residues can be found on all fingerprints and could be used to identify traces of items people came in contact with such as gunpowder, narcotics and biological or chemical weapons, as well as potentially being used to pin-point specific traits - like a persons sex or aspects of their diet - through spectroscopic analysis. Imperial scientists led by Professor Sergei Kazarian from Imperial College London’s Department of Chemical Engineering found that the use of commercial gelatine based tape provides a simple method for collection and transportation of prints for chemical imaging analysis.
The prints, once lifted, are analyzed in a spectroscopic microscope. The sample is irradiated with infrared rays to identify individual molecules within the print to give a detailed chemical composition. The information is then processed by an infrared array detector, originally developed by the U.S. military in smart missile technology. The array detector chemically maps the residue. This process builds up a picture, or chemical photograph, and allows for the most comprehensive information obtained from a fingerprint.
Chemical clues could also highlight specific traits in a person. A strong trace of urea, a chemical found in urine, could indicate a male. Weak traces of urea in a chemical sample could indicate a female. Specific amino acids could potentially indicate whether the suspect was a vegetarian or meat-eater. Also by focusing on what is left in a fingerprint after a period of time, scientists could potentially gauge how old a crime scene is.
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