A new fingerprinting technique could potentially detect the diet, race and sex of a suspected criminal, according to new research published in the August edition of the journal Analytical Chemistry.
The team, led by Professor Sergei Kazarian from Imperial College London's Department of Chemical Engineering, has devised a technique which collects fingerprints along with their chemical residue and keeps them intact for future reference.
Chemical residues contain a few millionths of a gram of fluid and can be found on all fingerprints. Conventional fingerprinting techniques often distort or destroy vital chemical information with no easy way of lifting residues for chemical imaging, until now.
Imperial scientists found that the use of gel tapes, commercial gelatine based tape, provides a simple method for collection and transportation of prints for chemical imaging analysis.
The prints, once lifted, are analysed 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.
"The combined operational advantages and benefits for forensic scientists of tape lifting prints and spectroscopic imaging really maximises the amount of information one can obtain from fingerprints. Our trials show that this technique could play a significant role in the fight against crime," said Professor Kazarian.
In many cases, this information is enough to determine valuable clues about a person beyond the fingerprint itself. It could potentially identify traces of items people came in contact with, such as gunpowder, narcotics and biological or chemical weapons.
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.
Professor Kazarian believes that this technique could allow forensic scientists to observe how fingerprints change in time and within different environments.
"By focussing on what is left in a fingerprint after periods of time, scientists could potentially gauge how old a crime scene is. Studying what happens to prints, when they are exposed to high temperatures, could also be particularly significant, especially in arson cases where lifting prints has been notoriously hard," he said.
Speculating about the possible future benefits of this process, Professor Sergei Kazarian said:
"In the courtroom of the near future, chemical images could feature as key evidence. I hope our work assists law enforcement authorities to bring dangerous criminals to justice."
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Notes to Editors:
1. "Spectroscopic Imaging of Latent Fingermarks collected with the aid of gelatine tape" Journal of Analytical Chemistry, 1 August 2007. Anal. Chem. 2007, 79, 5771 - 5776.
The full listing of authors and their affiliations for the Analytical Chemistry paper is as follows: Camilla Ricci(1), Steve Bleay(1), Sergei Kazarian(1) (1) Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
2. Analytical Chemistry web address:
3. About Imperial College London Rated as the world's ninth best university in the 2006 Times Higher Education Supplement University Rankings, Imperial College London is a science-based institution with a reputation for excellence in teaching and research that attracts 11,500 students and 6,000 staff of the highest international quality. Innovative research at the College explores the interface between science, medicine, engineering and management and delivers practical solutions that improve quality of life and the environment - underpinned by a dynamic enterprise culture.
With 66 Fellows of the Royal Society among our current academic staff and distinguished past members of the College including 14 Nobel Laureates and two Fields Medallists, Imperial's contribution to society has been immense.
Inventions and innovations include the discovery of penicillin, the development of holography and the foundations of fibre optics. This commitment to the application of our research for the benefit of all continues today with current focuses including interdisciplinary collaborations to tackle climate change and mathematical modelling to predict and control the spread of infectious diseases.
The College's 100 years of living science will be celebrated throughout 2007 with a range of events to mark the Centenary of the signing of Imperial's founding charter on 8 July 1907.