Study of surface-enhanced infrared absorption spectroscopy (SEIRAS) of black inkjet prints using silver colloid

Only black inkjet prints were studied with regard to forensic examination of documents. We analysed twenty-one inkjet prints using surface-enhanced infrared absorption spectroscopy (SEIRAS). The present paper deals with micro-destructive document analysis based on silver nanoparticles (AgNPs) use to obtain surface enhanced ATR-FTIR (attenuated total reflection - Fourier transform infrared) spectra directly from the document. For this experiment, AgNPs in colloid form was applied. AgNPs for SEIRAS analyses were synthesised and afterwards analysed by scanning electron microscopy (SEM). The purpose of the enhancement of colloids was to improve the resolution of the absorption signal of the analysed samples from noise. In the experiment, the obtained ink ATR-FTIR spectra, with and without silver treatment, were significantly affected by the paper base.