Problems of Forensic Sciences 2001 Vol. 46 (XLVI) 413-427
IDENTIFYING BLACK TONERS USING FTIR AND PYROLYSIS-GC/MS
Jan A. de KOEIJER, Johannes J. M. de MOEL
Netherlands Forensic Institute, Rijswijk, the Netherlands
Streszczenie
For the analysis of toner using Fourier transform infrared spectroscopy (FTIR) and pyrolysis gas chromatography with mass selective detection (pyrolysis-GC/MS) a previously reported sampling method using a heat transfer of the toner from the paper to a medium was revised to give more stable results whilst causing less damage to the document. To sample the toner home made stainless steel discs with polished surfaces are heated to 180°C and then applied to the document for about two seconds. The toner adhering to the discs gives a good representative sample and is used for both methods of analysis. No visible damage is done to the document. The analysis of the toner consisted of two parts, a screening method using FTIR and a highly discriminative method applying pyrolysis-GC/MS. For the screening the FTIR microscope in transmission mode was found to give the best results, dividing the toner test set into several different classes. Further differentiation within the toner classes was achieved with pyrolysis-GC/MS.
Słowa kluczowe
Questioned documents; Toner; Photocopy; Fourier transform infrared spectroscopy; Pyrolysis-GC/MS; Heat transfer sampling.