Individual fibres identified by new forensic test

‘White cotton fibres are so common and have so few visual distinguishing features that they are largely ignored by forensic scientists at crime scenes,’ said Brian Strohmeier, a scientist at Thermo Fisher Scientific in the US.

Most fabrics go through various manufacturing and treatment processes – for example, to make them stain resistant, waterproof, or iron-free – leaving unique organic chemicals on the surface of the fibres. By analyzing the chemical signature on the surface of individual fibres, forensic scientists can identify the origin of scraps of fabric evidence found in crime scenes.

Strohmeier will describe this work at the AVS 60th International Symposium and Exhibition in Long Beach, California, which is held between October 27 – November. 1, 2013.

In the new method, Strohmeier and his colleagues used X-ray photoelectron spectroscopy (XPS). In XPS, the test sample is struck with a focused X-ray beam, which removes electrons from the surface of the sample. A detector then counts the electrons and measures their kinetic energies, with the resulting spectrum revealing the chemical signature of the surface.