Volume 90 Issue 46 | p. 29 | Concentrates
Issue Date: November 12, 2012

Mass Spec Method Fingerprints Dyed Fibers

Technique causes minimal damage to forensic evidence, allows cross-checking of crime scenes with suspects
Department: Science & Technology
News Channels: Environmental SCENE
Keywords: forensic science, mass spectrometry, textile, criminal evidence
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Mass spectrometry can now identify the fiber (yellow, left) and its dye (blue, right) in cross sections of nylon fibers.
Credit: Anal. Chem.
This is an image of dyed fibers analyzed by mass spectrometry.
 
Mass spectrometry can now identify the fiber (yellow, left) and its dye (blue, right) in cross sections of nylon fibers.
Credit: Anal. Chem.

Forensic scientists hoping to cause minimal damage to critical evidence may have a new analytical technique to study suspicious fibers found at crime scenes (Anal. Chem., DOI: 10.1021/ac3025569). Chuanzhen Zhou, David Hinks, and coworkers at North Carolina State University developed a mass spectrometry method to identify dyes on nylon, and they are now working to extend the technique to polyester and cotton fibers. The researchers first clean the fiber surface by using a C60+ fullerene ion beam and then use Bi+ ion beam time-of-flight secondary ion mass spectrometry to take a chemical fingerprint of the dye, fabric, and any other trace material on the fiber surface. Hinks says the technique could provide essential backup for existing forensic fiber analysis techniques while consuming an insignificant amount of the evidence to do the experiment. Most forensic labs currently use polarized light microscopy to identify fibers, and some labs then extract dye from the fiber and analyze it by thin-layer chromatography, he notes. By analyzing fiber and dye together in situ, the new technique will allow researchers to identify the material’s trace contaminants for additional comparison between fibers obtained from crime scenes and from suspects, the researchers suggest.

 
Chemical & Engineering News
ISSN 0009-2347
Copyright © American Chemical Society

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