"Mass spectrometry has been used in forensics for decades to look for explosives and illicit substances," Dorrestein told Seeker. "However, those technologies are typically done in a targeted manner, looking for specific modules. We decided to take a global look at the molecules that are present on objects they touch."
The process involves analyzing literally everything that's swabbed off the phone. Then each sample is run through a massive database of specific molecules present in various commercial products, foods and medicines. In their testing, the research team was able to identify a wide range of products and substances - for example, an allergy medication, a particular type of sunscreen, or even a specific brand of soft drink.
"We realized that this can be used to build a composite lifestyle sketch from all the molecules we detect," Dorrestein said. "Each molecule is a little clue, and there are hundreds to thousands of clues from a single sample."
The collective data obtained by this kind of global analysis provides the "lifestyle sketch" for the owner of any given phone. The process can also be used on other personal objects, such as keys or handbags, say.
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"These findings introduce an additional form of trace evidence from skin-associated lifestyle chemicals found on personal belongings," the scientists wrote. "Such information could help a criminal investigator narrowing down the owner of an object found at a crime scene, such as a suspect or missing person."
Dorrestein said that the system could potentially have other applications beyond forensics. Marketers might be interested in this kind of lifestyle information, but that there are no plans to develop the technology beyond law enforcement. The system currently uses an open-source database which Dorrestein's group has developed.
"We capture in a crowdsourced fashion the collective knowledge that can be captured by mass spectrometry," he said. "The database is public and free to access by anyone."
The research was published in the journal Proceedings of the National Academy of Sciences.