New technique IDs substances, not just fingerprints

Law enforcement has a powerful new tool – mass spectrometry.

The technique to measure the chemical composition of a sample isn't a new technology but, writing in Science, R. Graham Cooks has identified a variation that will allow crime labs to identify not only the identity of a fingerprint but also the substances the fingers have touched.

The Times explains:

In Dr. Cooks’s method, a tiny spray of liquid that has been electrically charged, either water or water and alcohol, is sprayed on a tiny bit of the fingerprint. The droplets dissolve compounds in the fingerprints and splash them off the surface into the analyzer. The liquid is heated and evaporates, and the electrical charge is transferred to the fingerprint molecules, which are then identified by a device called a mass spectrometer. The process is repeated over the entire fingerprint, producing a two-dimensional image.

But wait, there's more. The technique -- desorption electrospray ionization – identifies not just the presence of the substance but a pattern in the shape of the fingerprint, positively identifying that a certain person had touched cocaine, for instance.

Dr. Cooks' goal is not better forensic analysis, though. It's helping to combat cancer.

If a Desi analyzer can be miniaturized and automated into a surgical tool, a surgeon could, for example, quickly test body tissues for the presence of molecules associated with cancer.

Instead of drug tests, a company could surreptitiously check for illegal drug use by its employees by analyzing computer keyboards after the workers have gone home, for instance.