Analytical Differentation of Black Powder Toners of Similar Polymer Composition for Criminalistic Purposes

The aim of this research was to investigate the possibility of differentiation between black powder toners of similar polymer composition applying analytical methods: Fourier transform infrared spectrometry (FTIR) and X–ray fluorescence spectrometry (XRF). The studied materials were black powder toners of similar polymer composition sampled from the cartridges of 34 machines (31 models purchased from 11 manufacturers). Due to similar polymer composition only small differences in IR spectra of the investigated powders were observed, such as the appearance of peaks of weak intensity or modified shapes of the spectra. However, for eight samples the observed differences were sufficiently significant to regard these samples as chemically different. In cases when the differences in IR spectra were significantly smaller, XRF method was used to differentiate the samples. The samples differing in respect of elemental composition were regarded as different and, accordingly, the corresponding differences in the IR spectra were regarded significant. The proposed analytical procedure may be applied to forensic examination of documents.