NCJ Number
205133
Journal
Journal of Forensic Sciences Volume: 49 Issue: 2 Dated: March 2004 Pages: 238-249
Date Published
March 2004
Length
12 pages
Annotation
This study examined the effectiveness of using liquid chromatography mass spectrometry (LC-MS) to identify dyes extracted from textile fibers.
Abstract
Textile fibers are frequently encountered in forensic work as evidence in criminal investigations. An important component of fiber examination is the identification of textile dyestuffs for the purpose of establishing a common source of a fiber. Electrospray ionization (ESI) is one of the most universal techniques for the ionization of nonvolatile and thermally-labile molecules and ESI-MS is a powerful method for identifying textile dyes. The current study analyzed a set of 22 reference dyestuffs and 10 dyes extracted from textile fibers using LC-ESI-MS. The objective of the study was to demonstrate the usefulness of the LC-MS methodology for effectively identifying dyes extracted from textile fibers. Dyes were extracted from fibers into equal parts methanol and water mixtures. Monitoring the elution of dyes in the presence of other non-dye components was facilitated by placing a UV-visible absorbance detector in a series before the MS detector. Results indicated that dyes used in the textile industry are highly varied in chemical structure, rendering their ionization efficiencies and MS sensitivities also highly varied. Six of the extracted dye samples corresponded to dye samples contained in the set of 22 reference dyestuffs; however, 4 of the extracted dyes did not correspond to the reference dyestuff. A solution of 0.3 percent triethylamine (TEA) added to the water reservoir of the mobile phase was used to enhance the analysis of dyes containing multiple sulfonate groups. The addition of TEA was shown to enhance the ESI-MS response of these dyes. Through this methodology, dye identification is practical even in the absence of a comparison dye standard. Future research should test the compatibility of the LC-MS method with fiber dye extraction solvent systems and protocols put forth by the Federal Bureau of Investigation. Tables, figures, references