title: [The study of adsorption of L-aspartic acid on silver sol by surface-enhanced Raman scattering].
abstract: The adsorption state and the characteristics of L-aspartic acid adsorbed on silver sol were studied by the Surface-Enhanced Raman Scattering (SERS) method. Strong Raman signals were detected in the experiments. The results suggested that L-aspartic acid adsorbed on the silver surfaces through carboxyl and nitrogen atoms since the signals were mainly due to the carboxyl and the nitrogen of the molecule of L-aspartic acid. The adsorption of carboxyl on the silver surfaces is chemical adsorption, which is based on the mechanism of charge-transfer, while the adsorption of nitrogen on the silver surfaces is physical type, which is due to the electromagnetic mechanism. The intensity of surface-enhanced Raman scattering of L-aspartic acid adsorbed on silver surface was also analyzed, and it was found that the intensity of surface-enhance Raman scattering will change with different concentrations of L-aspartic acid adsorbed on the silver surfaces. The intensity will reach the top value when the concentration of L-aspartic acid was 10(-3) mol x L(-1). When the concentration of L-aspartic acid decreased to 10(-4) mol x L(-1), the intensity of surface-enhanced Raman scattering became a little weaker than that with 10(-3) mol x L(-1). With further decrease in the concentration of L-aspartic acid, the intensity of surface-enhanced Raman scattering also decreased gradually. When the concentration of L-aspartic acid decreased to 10(-6) mol x L(-1), the intensity of surface-enhanced Raman scattering was very low. The above study will be helpful to the further study of peptide and other complex biological systems.
authors.affiliation: Department of Chemistry, Tongji University, Shanghai 200092, China.
authors.forename: Zhi-liang
authors.initials: ZL
authors.lastname: Zhu
authors.forename: Jun-ying
authors.initials: JY
authors.lastname: Gao
authors.forename: Feng-ting
authors.initials: FT
authors.lastname: Li
authors.forename: Bing-ru
authors.initials: BR
authors.lastname: Zhang
mesh_terms: D000327:Adsorption; D001224:Aspartic Acid / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry; D010455:Peptides / Q000737:chemistry; D012834:Silver / Q000302:isolation & purification*; D018030:Silver Compounds / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D020349:Surface Plasmon Resonance / Q000379:methods
chemical_list: D010455:Peptides; D018030:Silver Compounds; D001224:Aspartic Acid; D012834:Silver; D009584:Nitrogen