Surface enhanced Raman scattering of pyrazole adsorbed on silver colloids

SERS spectra of pyrazole adsorbed on silver hydrosol at different pH values and on silver colloidal substrate deposited on filters were obtained and i nterpreted on the basis of the existence of three forms in equilibrium, cat ionic, neutral and anionic. SERS data indicate that the neutral molecule is preferentially adsorbed in acidic environment, pyrazolide anion is instead favoured over all the other pH values. Addition of chloride anions induces the formation of reaction products when pyrazole is adsorbed on silver hyd rosols, while this effect is missing on dry silver substrate. (C) 1999 Else vier Science B.V. All rights reserved.