Examination of Firearms Review: 2007 to 2010 - Interpol

Morgan et al [43] studied the statistical validity of discrimination between
various polymer classes and dyed textile fibres, visualisation of significant
differences between groups of spectra discrimination, and tracking of spectral
changes with environmental changes. Fibres and associated spectra
contained in the database, combined with validated software, are useful for
fibre comparisons in casework and for quality control and the training of
analysts. This paper describes the application of linear discriminant analysis
to a database containing more than 5,000 UV/visible absorbance and
fluorescence spectra.
Abendshien et al [44] Reported on the development of the FBI Forensic
Automotive Carpet Fibre Identification Database (FACID). At present, FACID
contains more than 700 automotive carpet samples from private vehicles and
vehicle manufacturers. Questioned carpet-type fibres can be searched by
microscopic characteristics, fibre type, and/or colour information in order to
determine whether or not a particular type of vehicle was involved in the
commission of a crime. FACID can also be searched by vehicle make, model,
year, and/or colour in order to determine the carpet samples available for
comparison.
Ali et al [45] this study, a natural dye extracted from Eucalyptus camaldulensis
was used to colour cotton fabric by direct dyeing under a range of different
conditions. The aim of this work was to compare the fastness properties of
dyeing by different dyeing techniques. This dye shows fairly good saturation
on cotton and has medium-to-good fastness properties.
Morgan et al [46] assessed whether forensic fibre discrimination could be
improved by extracting the dye from the fibre prior to trace analysis by a highresolution
separation technique. Methods developed for the extraction of
unknown dyes from fibres, were based on three capillary electrophoresis (CE)
procedures for dyes from six classes of textile dyes. CE with diode array
detection is useful for the analysis of longer-length fibres, but a more sensitive
and selective method, such as CE/mass spectrometry (MS) is required for the
analysis of the small amount of dye (2-200 ng) associated with forensically
relevant fibre samples. The analytical approach was destructive, but only an
extremely small sample (approx. 2 mm of a single 15-um diameter fibre) was
required. CE/MS analysis was found to be capable of separating extracted
dye components and providing semi-quantitative estimates of dye amounts
whilst providing qualitative information for the identification of dyes.
Eng and Bhagwandin [47] investigated the effect of metamerism in the
generation of different UV-visible spectra. Metameric samples of blue textile
fibres, created using different colouring agents or different relative
concentrations of the colouring agents, were examined in order to
demonstrate their differentiation based on their spectra between 350 and 800
nm using UV-visible microspectrophotometry. It was found that some of the
metameric samples intersected at three or more loci, but some did not
intersect at all. In the intersecting spectra, there was no correlation between
either the dye chemistries of the relative component concentrations.
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