How Old Is That Fingerprint?
While forensic scientists have, for more than a hundred years, been able to opine that a fingerprint came from a particular person, the limitations of science did not permit them to state when the fingerprint was left by that person.
But that limitation may have been recently shattered. Using a method of matrix-assisted laser/desorption ionization mass spectrometry (“MALDI-MS”), researchers were able to track shifting levels of triacylglycerols (body oil). Pinning down the time the person touched the object and left the fingerprint would assist investigators in establishing a better timeline, in ruling out a suspect or in contradicting one’s story.
The new study, published in Analytical Chemistry by researchers Paige Hinners, Madison Thomas, and Young-Jin Lee from Iowa State University, indicates the researchers could reliably determine the triacylglycerol degradation rate for each person over the course of seven days.
“Most compounds in fingerprints can be measured using this technique,” said Lee. “But we focused on triacylglycerols as they are highly abundant and much more reliably measured than others.” The rate of degradation differed according to each individual, and more testing needs to be done using the MALDI-MS to account for multiple variables such as environmental factors and experimental conditions.
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