Research: Analyzing Fingerprints
Dyson Associate Professor Rita Upmacis, PhD, is exploring the potential for a new approach to forensic fingerprint analysis: chemistry.
You’re a detective, combing a crime scene for clues. By all appearances, the perpetrator was careful—there are no witnesses, nothing left behind. But you’re cool as a cucumber, because you’ve just dusted the credenza and discovered a big, beautiful fingerprint, perfectly intact. Confidently, you reach out with your rubber tape to lift the print, and—oops! You smeared it. Real smooth. Did you just blow your only lead?
If a chemistry professor at Pace can help it, not necessarily. Of course we all know that the ridges and furrows of a fingerprint are unique to an individual, and DNA analysis has taken off recently as well. But DNA evidence can often be difficult to obtain, and, as we’ve seen, fingerprints don’t always come whole. What if there was a third method of identifying people?
From her time as a researcher at Weill Cornell Medical College studying atherosclerosis (the clogging of blood vessels), Pace Associate Professor Rita Upmacis, PhD, developed an interest in the lipids in the plaque that builds up on artery walls. She explains, “I’ve always been interested in fatty acids, and I wanted to extend this idea to see if we could analyze the fatty acids in fingerprints.” Why fingerprints? As it turns out, we’re all a little different from each other, chemically speaking. “A dog, for example,” says Upmacis, “can identify its master by the scent that results from a unique combination of oils.” The same principle, she concluded, might be applicable to the oils left by fingerprints.
Enter mass spectrometry—a method of identifying chemicals in a sample by mass. Inspired by new advances in the technology, Upmacis worked with undergraduate student Ivelisse Dyson ’16 to test her hypothesis. Gathering six test subjects, they washed their fingertips with ethanol and analyzed the ethanol washes with a leading-edge mass spectrometer. What they found amazed Upmacis. “When we started, we weren’t sure what we were going to find. I was thinking we would detect maybe six to ten lipids for each individual.” Instead, she found that there were more than 100 lipids per individual—in some cases, more than 200.
“The upshot,” says Upmacis, “is that there’s a lot of information contained in the oils in our fingerprints. This composition can be influenced by dietary factors, genetic factors, environmental factors, things we’ve touched, moisturizers we’ve used. The point is that the variation in these oils tells us something about the person.”
The research is still in its early stages. The day-to-day variation in a person’s oil composition is still something that needs to be better understood, and considering the sheer number of lipids in a person’s fingerprint, it’s difficult to know what exactly to focus on. “It’s a big project,” says Upmacis. “We’ve realized that it’s possible, but it’s going to take a lot more work. Sometimes you go into a project with a question, and what you get is 10 new questions.”
Still, the potential is exciting. While traditional fingerprint analysis can only be used for rudimentary matching, when it comes to chemical analysis we might eventually be able to glean all kinds of information, such as the age and gender of the person, or whether the person is a smoker or a vegetarian. And it’s not just about forensics—it’s easy to see how this research could have implications in medicine and other fields.
So can you nab your criminal? Maybe not just yet, but you might want to holdon to a swab of that smeared fingerprint.
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