2007 Volume 56 Issue 12 Pages 1147-1152
The forensic discrimination of photocopied characters was examined by the combination of data, such as morphological observations and elemental analyses by SEM/EDX, resin ingredient analyses by Pyr-GC/MS and microscopic FT-IR, and organic additives analyses by HPLC. As an obtained result, a significant morphological difference was observed between each sample, and also characteristic elements, for instance Si, Fe, Cu and Cr, were detected by EDX analyses. The result obtained from Pyr-GC/MS showed that the utilized resin consisted of a styrene-type resin, and spectra obtained by micro FT-IR analysis; these resins were divided to three groups: a styrene/methylmetacrilate copolymer was used in samples 1 and 2. In contrast with this result, a styrene/acryle/epoxy copolymer resin was used in samples 3 and 4. In order to analyze organic additives, part of character was subjected to an extractor by acetonitrile, and HPLC was conducted. Comparisons of HPLC chromatograms of extractives from a part of the character on the examined four different kinds of photocopies, significant difference were observed between them. The protocol established by this examination could completely discriminate the 4 photocopied materials. This procedure was applied to an actual blackmail case. The character on the blackmail and burned dust of the paper existed in deposited soils in front of the suspect's house; their similar character was clarified by this analytical protocol. This result reinforced an investigation by information provided from a scientific evidence examination.
