ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Differentiation of selected blue writing inks by surface-enhanced Raman spectroscopy

Ľubomír Vančo, Magdaléna Kadlečíková, Juraj Breza, Pavol Michniak, Michal Čeppan, Milena Reháková, Eva Belányiová, and Beata Butvinová

Faculty of Electrical Engineering and Information Technology, Slovak University of Technology in Bratislava, Ilkovičova 3, SK-812 19 Bratislava, Slovakia

E-mail: juraj.breza@stuba.sk

Abstract: Raman spectroscopy and surface enhanced Raman spectroscopy were used to examine 14 blue inks obtained from commercially available stationery. Standard colouring agents in the inks: β-phase of phtalocyanine blue PB15 and some homologues of the methyl violet class, were identified. Surface enhanced Raman spectra were recorded on a firm heterostructure of silver/nanocrystalline diamond/silicon constituting an active substrate providing the possibility to write directly on the surface. Based on the differences in traditional and surface enhanced Raman spectra, two inks were identified unambiguously, the remaining inks were categorised into three groups exhibiting common spectral features. Despite their similarity, surface enhanced Raman spectra exhibited soft variations enabling discrimination of the inks, thus proving the usefulness of the method.

Keywords: blue ink – Raman spectroscopy – surface enhanced Raman spectroscopy (SERS)

Full paper is available at www.springerlink.com.

DOI: 10.1515/chempap-2015-0068

Chemical Papers 69 (4) 518–526 (2015)