When you watch forensic dramas on TV, it seems easy to figure out who did a crime when fingerprints are left at the scene. In reality, fingerprint oils break down over time, making it hard to figure out how old they are.

Now, in a small study published in ACS Central Science, researchers have found molecular markers that show how these oils change over a seven-day period. This information could be used to figure out the ages of fingerprints more accurately.

The age of fingerprints found at a crime scene can provide crucial information about who was present when a crime was committed.

Young Jin Lee and his colleagues had already shown that triacylglycerols in fingerprint oils react with ozone in the air to make oxidation products that can be used to figure out when fingerprints were created.

However, squalene, wax esters, fatty acids, and diacylglycerols are among the oils that react with ozone to produce a complex variety of oxidation products.

So, Lee and Andrew Paulson wanted to come up with a way to figure out what this mix of chemicals means and find molecular markers that could more accurately tell how old a fingerprint is.

A volunteer was asked to imprint 14 thumbprints on glass slides, which the researchers then left at room temperature in the open for up to seven days.

After that, the scientists used high-resolution mass spectrometry to examine the fingerprint oils. Using a Kendrick mass defect plot, a specialised data visualisation tool, they found two new, distinct molecular trends: the existence of epoxides, and an increase in medium-length fatty acids.

Epoxides, which are generated from triacylglycerols, wax esters, fatty acids, and diacylglycerols, were detected in the fingerprints, albeit their utility in predicting fingerprint age remains to be determined.

Capric acid and decanoic acid, both saturated fatty acids with 10 carbons, were found in far higher concentrations than expected, and the researchers speculate that this is due to ozone reacting with certain carbon-carbon double bonds that are exclusive to human fingerprints.

The next stage, according to the researchers, is to create a model based on the findings to ascertain when fingerprints were left.

The authors appreciate funding from the National Institute of Justice in the United States.

Source: 10.1021/acscentsci.2c00408

Image Credit: Getty

You were reading: Discovered Two New Unique Molecular May Help Reveal Fingerprints’ Ages More Accurately