Foiling Criminals With New X-ray Fluorescence Fingerprinting

Scientists from the US are giving a helping hand to forensics with a new technology that detects otherwise invisible fingerprints. Traditional fingerprinting methods involve adding dust or liquid that sticks to greasy prints. The pattern revealed can then be used to catch the criminal. But there are problems with this method, including difficulties with spotting fingerprints on wood, leather, plastic and those belonging to children. The new method uses Micro-X-Ray Fluorescence (MXRF), which can detect fingerprints by the salts found in sweat, such as sodium chloride and potassium chloride. When a person touches something, the pattern of salts they leave behind matches the pattern of ridges on the finger, and so makes the invisible visible. By gathering details about the salts in a fingerprint, scientists can even discover if a person was handling explosives, which would be signalled by high levels of potassium. The technique is designed to be used alongside traditional methods and should be ready for commercial use in two to five years.