Scientists at Los Alamos National Laboratory have devised a new method to detect the chemical residue left behind by your fingertips. They used micro-X-ray fluorescence (MXRF) to reveal the sodium, potassium, chlorine, and other elements excreted in sweat and deposited in a fingerprint pattern. From Los Alamos News:
The technique has several advantages over traditional fingerprint detection methods that involve treating the suspect area with powders, liquids, or vapors in order to add color to the fingerprint so that it can be easily seen and photographed. Using this technique, known as contrast enhancement, it is sometimes difficult to detect fingerprints present on certain substances, such as multicolored backgrounds, fibrous papers and textiles, wood, leather, plastic, adhesives and human skin.
Since MXRF is noninvasive, a fingerprint analyzed by the method is left pristine for examination by other methods like DNA extraction.
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