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Importance of Thin Layer Chromatography and UV Microspectrophotometry in the Analysis of Reactive Dyes Released From Wool and Cotton Fibers

NCJ Number
209098
Journal
Journal of Forensic Sciences Volume: 50 Issue: 2 Dated: March 2005 Pages: 364-368
Author(s)
Kenneth G. Wiggins; Julie-Ann Holness B.Sc.; Bridget M. March B.Sc.
Date Published
March 2005
Length
5 pages
Annotation
This study demonstrated the value of using thin layer chromatography (TLC) and/or ultraviolet (UV) range microspectrophotometry as well as comparison microscopy (CM) and visible range microspectrophotometry (VS) when comparing fiber samples.
Abstract
Reactive dyes encountered in casework have increased significantly over the last 10-15 years. The current study selected red as a color for analysis because the end result is often achieved by using a single component dye, thus making the detection of a second dye or shading colors less likely. This could add to the problem of differentiating between similarly colored samples of the same fiber type. Black and blue cotton were included in the analysis because they are two of the most common fiber/color types encountered in forensic textile fiber examination. This paper describes the analytical pathway followed, which included the use of CM, UV range microspectrophotometry, VS, and TLC. Although the set of black cottons examined were not further differentiated when UV microspectrophotometry or TLC was used, these techniques helped with the differentiation of the red wool and the blue cotton. If the concentration of dye in the fiber is not sufficient for TLC or prevention of the destruction of the fiber is required, a UV spectrum can usually be obtained, which allows for the possibility of further differentiation. 3 tables, 2 figures, and 8 references