Scientists pick sex and eating habits from a drop of sweat and fingerprint

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It is the stuff crime novels are made of - the ability to tell a suspect's sex, diet and smoking habits, all from a single drop of sweat.

Soon, police could have such technology at their fingertips, with the development of a technique that allows them to build up a profile of a suspect from nothing more than a fingerprint.

Scientists at Imperial College London have shown that fingerprints contain vital information about a person's habits.

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Scientists can tell what someone has eaten from sweat and fingerprints

From analysing the layer of sweat and grease left behind when someone touches a surface, they can tell whether the hand in question belonged to a man or a woman.

The chemical pattern can also provide clues about a person's eating habits, with the proteins present, for instance, giving a pointer as to whether they are vegetarian.

Even nicotine could be picked up.

With the analysis carried out on lab equipment that is already available, the scientists behind the technique believe it could be ready for use at crime scenes in as little as a year.

Professor Sergei Kazarian, a physical chemist, said: "It is up to law enforcement agencies to invest the money to buy the equipment and in training.

"In the courtroom of the near future, chemical images could feature as key evidence.

"I hope our work assists law enforcement authorities to bring dangerous criminals to justice."

Key to the technique, which is reported in the journal Analytical Chemistry, is the collection of the sweat, grease and other liquid left behind with a fingerprint.

Traditional methods of fingerprint collection, which use a combination of powder, chemicals and tape, tend to distort the chemical make up of the residue.

However, the Imperial researchers have shown both the print and the residue can be safely transported to the lab using a gelatine-based sticky tape more usually used to collect footprints.

Once there, highly sensitive infra-red technology, originally developed by the US military for use in smart missiles, is used to analyse the residue and provide a breakdown of all the chemicals present.

Using prints collected from door handles, mug handles and car doors, the researchers have shown that the residue provides vital information about sex, with men's prints tending to have higher levels of urea, a chemical found in urine, than women's.

Similarly, the residue left behind also contains clues as to person's diet, including whether they are a meat-eater.

It may even be possible to detect traces of drugs and gunpowder and even biological or chemical weapons.

In addition, deterioration of the components of the residue could provide information as to how old a crime scene is.

Prof Kazarian said: "The combined operational advantages and benefits for forensic scientists of tape lifting prints and imaging really maximises the amount of information one can obtain from fingerprints.

"Our trials show that this could play a significant role in the fight against crime."

A Home Office spokesman said: "We are always reviewing new technology and developments in science."

 

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