SERS active substrates for neonicotinoids studies

Different basic substrates, - Si wafers, (001) SiO2, printer paper, Al2O3, microprocessed (001) SiO2 or diamond abrasive films, have been used to create active Ag and Au nanostructures. In this lecture, we report the use of pulsed-laser deposition and thermal deposition both followed by pulsed-laser annealing; the results are compared. Advanced substrates of Au and Ag on Si were produced in view of surface-enhanced Raman spectroscopy (SERS) detection of the imidacloprid (Nuprid 200 SP) neonicotinoid insecticide in amounts much smaller than those ordinarily applied in agricultural medicine. The SERS peaks intensity rose by at least one order of magnitude after the pulsed-laser annealing of the metal films and nanoparticles arrays formation. The enhancement factor (EF) was estimated to be >5x10(4), the limit of detection (LOD) reached being < 0.5 nM. The properties of the advanced substrates were compared and discussed. The importance of SERS as a relatively inexpensive and simple method is emphasized in regulating, monitoring and controlling the level of such chemicals as environmental pollutants, thus precluding harming the human and, especially, honey bees' health.