If worries about personal data held inside your phone keeps you up at night, you might want to give the outside of your phone a scrub.

Scientists say they can deduce the lifestyle of an individual, down to the kind of grooming products they use, food they eat and medications they take, from chemicals found on the surface of their mobile phone.

Experts say analysis of someone’s phone could be a boon both to healthcare professionals, and the police.



“You can narrow down male versus female; if you then figure out they use sunscreen then you pick out the [people] that tend to be outdoorsy - so all these little clues can sort of narrow down the search space of candidate people for an investigator,” said Pieter Dorrestein, co-author of the research from the University of California, San Diego.

Writing in the Proceedings of the National Academy of Sciences, researchers from the US and Germany describe how they swabbed the mobile phone and right hand of 39 individuals and analysed the samples using the highly sensitive technique of mass spectrometry.

The results revealed that each person had a distinct “signature” set of chemicals on their hands which distinguished them from each other. What’s more, these chemicals partially overlapped with those on their phones, allowing the devices to be distinguished from each other, and matched to their owners.

“If one looks at the hands of an individual they are unique in 99% of the samples investigated. In two cases we could not do that perfectly, but in one of those cases people lived together,” said Dorrestein. “In 69% of the cases we could perfectly match up the chemical profile, the molecular profile, on the phone to the person that it belonged to.”

But, he adds, the promise of the technique lies not in identifying individuals, but in building a profile of the phone’s owner.



Analysis of the chemical traces using a reference database allowed the team to match the chemicals to known substances or their relatives to reveal tell-tale clues from each individual’s life - from whether they use hair-loss treatments to whether they are taking antidepressants.

Some of the chemicals, such as the mosquito repellent DEET, were found more than four months after the product was last used by the phone’s owner.

The approach, the authors say, could be extended to produce a wide-ranging database that could be used by police to predict the lifestyle of an individual based on the specific set of trace chemicals found on their phone, keys or other objects.

They also suggest that the tool could be used for a variety of other purposes, such as monitoring the exposure of individuals to pollutants or checking whether patients are taking their medications or responding to certain drugs.

Melanie Bailey, an expert in forensic analysis at the University of Surrey, believes the approach could prove valuable. “The problem is if you have a mobile phone you can develop fingerprints from it, but those fingerprints are completely useless if either the donor isn’t on a database or the fingerprint is smudged,” she said. “The information that they have here could allow you to narrow down a list of suspects, or at least give you some intelligence on what kind of person you should be approaching.”

But John Bond, former head of forensic services at Northamptonshire Police and an associate professor in criminology at the University of Leicester, was less sanguine, pointing out that it is already possible to detect traces of firearms, explosives and illicit drugs on objects, and that it was less clear whether chemicals linked to lifestyle would help to pin down offenders. “The problem is they are not very discriminating things - if you were to find a particular brand of cosmetic it is not really going to narrow down for you who you would be looking for,” he said.