An evaluation of trace element analysis in the forensic investigation of fibre samples

The use of trace element analysis in the forensic examination of fibres has been investigated. Samples of both natural and synthetic fibres have been analysed to show that it is possible to both identify and discriminate between samples that would, by present methods, be considered indistinguishable. A number of wool garments of predetermined trace element composition were sent for wear for a period of nine months. The conditions and frequency of wear and cleaning were reported to enable their effect upon the trace element composition of these garments to be determined. The wool samples were analysed by both short (30 min) and long (50 hrs) irradiations in a reactor flux of about 10¹² n·cm⁻²·sec⁻¹. This permitted the concentrations of the elements such as sodium, chlorine, iodine, manganese, cobalt and chromium to be determined. Both sodium iodide and lithium drifted germanium detectors were used to measure the induced activity of the wool samples. The composition of a range of acrylic fibres from a variety of sources has also been examined using a sodium iodide detector. The concentrations of sodium chlorine, bromine, managese, copper, aluminium, titanium, indium and barium were determined in these samples.