NCJ Number
148188
Journal
Journal of the Forensic Science Society Volume: 34 Issue: 1 Dated: (January-March 1994) Pages: 23-27
Date Published
1994
Length
5 pages
Annotation
This study investigated the effects of ageing and weathering on certain techniques used to identify shoe polish marks on clothing.
Abstract
Small samples of shoe-polish-stained, aged, and weathered materials were prepared for analysis by extracting the stains from the fabric into 1.0 ml of tetrahydrofuran in an ultrasonic bath for 30 minutes. The fabric was removed from the extract and solid residues were removed by centrifuging at 10,000 g for 5 minutes. The supernatant was retained for analysis. The dyes in the extract were examined with UV/visible light spectrophotometry and thin layer chromatography (TLC). UV/Visible spectra were recorded with a Cecil Model 505 double beam spectrophotometer coupled to a Cecil CE 500 control-record module scanning between 260 nm and 640 nm. TLC was carried out on Kieselgel Si-60 plastic backed plates with a silica gel layer 0.2 mm thick. The dual solvent system of dichloromethane followed by chloroform/methanol/water 5/1.5/0.2v/v/v was used. The chromatograms were examined visually. Heat volatile components were examined by gas chromatography. The visible regions of the UV/Vis spectra of the nine polishes examined were essentially the same. The visible regions of the UV/Vis spectra of the 7-day-old stains were indistinguishable from those prepared from 1-day-old stains. Since the characteristics of the black wax shoe polish stains tested remained qualitatively unchanged after ageing shows that the techniques can be used for the identification of shoe polish stains for at least 48 days after the stain has been made. 5 figures and 3 references