Examination of Petroleum Products of High Relative Molecular Mass for Forensic Science Purposes by Synchronous Fluorescence Spectroscopy. I1: Discrimination Within an Arbitrary Set of Representative Samples

Synchronous fluorescence and ultraviolet absorbance spectroscopy are used in the examination of a collection of high relative molecular mass petroleum products that contains 118 samples drawn from forensic science work. Data from 22 defined spectral features of each sample are processed to show that within this sample set, and with a considerable reduction in the data finally used, the spectral patterns can be efficiently retrieved with a high level of sample discrimination and with an accompanying low level of spurious choices. The system gives results in good agreement with earlier conclusions drawn from case work on the basis of visual comparisons of spectral patterns of control samples and contact traces and will enable future evidential data to be more efficiently collected and its significance to be more precisely assessed.