Surface-enhanced Raman spectrum of Gly-Gly adsorbed on the silver colloidal surface

• Published in: Journal of molecular structure Vol. 977; no. 1; pp. 56 - 61
• Main Authors: Xiaojuan, Yuan, Huaimin, Gu, Jiwei, Wu
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 10.08.2010
• Subjects: Adsorption; Gly-Gly; pH-dependent; Raman spectroscopy; SERS; Silver colloidal; Time-dependent; Silver colloidal; Time-dependent; Raman spectroscopy; pH-dependent; SERS; Gly-Gly
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2010.05.009

Raman and SERS spectra of homodipeptide Gly-Gly and Gly were recorded and compared in this paper, and band assignment for the functional groups contained in these molecules was analyzed in detail. Time-dependent and pH-dependent SERS spectra of Gly-Gly molecule adsorbed on nano-colloidal silver surface were also studied. The time-dependent SERS spectra of Gly-Gly are characterized by the increase in intensity of bands primarily representing the vibrational signatures emanating from the amino and amide moiety of Gly-Gly molecule. It is found that the adsorption style of Gly-Gly on the silver colloid changes as time goes on; at 5 min after adding the sample to the silver colloid, Gly-Gly adsorbs on silver surface firstly through the carboxylate, amino and amide groups, and then the carboxylate group is far away from the silver surface at 10 min to 3 days. The SERS variation of Gly-Gly with the change of pH suggests that the adsorption style is pH-dependent, the different adsorption behavior of the Gly-Gly occurs on silver surface at different pH values.