For decades, police have used fingerprints to identify crime suspects, but there is no means of telling when a print was left, and that information can make or break a case. But now, researchers believe that they can date fingerprints using compounds within the fingerprint.
If the police can know when a fingerprint was left, they can use that information to identify people that were there when the crime was committed and eliminate fingerprints that were left long before the crime was committed. Scientists were previously able to use a gas chromatography mass spectrometer to narrow down the time frame of when prints were left to within eight days. The problem was that eight days is a long time, and investigators needed a much smaller window for the fingerprint information.
To better understand when fingerprints are deposited, Dr. Young Jin Lee and colleagues looked at the reaction between unsaturated triacylglycerols left in fingerprints and the ozone in the air. The researchers used fingerprints from three people. They used mass spectrometry imaging to determine triacylglycerol levels and were able to determine the triacylglycerol degradation rate over the course of a week. The rate of degradation was different between participants. One person’s levels declined much more slowly but the scientists believe that was due to the participant having higher lipid levels. The methodology also works on fingerprints that have been dusted with forensic powder.
More study is needed, but this was a good first step to developing a test for fingerprint aging. The study is published in ACS’ Analytical Chemistry.