Surface enhanced Raman scattering of nitroexplosives on nontraditional substrates

Surface Enhanced Raman Scattering (SERS) is normally obtained from nanoactive surfaces or colloids of group II-B metals, in particular of silver and gold. In this study another type of nanosurface has been explored seeking more reproducible Raman spectra than those obtained from metallic substrates. Compounds of elements of the fourth transition period were tested for SERS analysis of nitroexplosives. Titanium (IV) oxides were found to give good Raman Enhanced signals of target molecules. TNT and DNT increased their signal intensities for this technique and were evaluated for the increase in different excitation sources. Laser lines at 785, 532 and 514.5 nm were evaluated to determine relative SERS cross sections for various vibrational bands of the target nitroexplosives. Polymorphism seems to play an important role in the Raman signal enhancement when using metal oxides: high rutile percent mixtures with anatase gave higher Raman scattered signal enhancement.