FT-SERS研究非极性R侧链氨基酸在银胶体系中的吸附状态

利用傅里叶变换表面增强拉曼光谱(FT-SERS)研究了以L-蛋氨酸为代表的非极性R侧链氨基酸在纳米银衬底上的吸附状态和相互作用的特性，并结合浓度、pH值的变化探讨了吸附作用的特点和规律。实验结果表明, L-蛋氨酸在银胶上的最佳FT-SERS的浓度范围为10-3～10-4 mol·L-1;其pH范围以酸性、等电点、碱性而分段，当pH值在等电点附近及酸碱度过大时的FT-SERS都较差;L-蛋氨酸与纳米银的作用是通过氨基、羧基、硫与银的物理、化学吸附，其吸附态随着pH值的变化而改变。结合文献，对非极性R侧链氨基酸与纳米银的吸附特性作了总结，以期有助于对氨基酸、蛋白质、多肽、酶等相关领域更深入的研究。

Study on Adsorption of Nonpolar R-Side Amino Acids on Silver Nanoparticles by FT-SERS

The adsorption orientation and adsorption characteristics of aliphatic-nonpolar amino acids represented by L-methionine on silver nanoparticles were studied by FT-surface-enhanced Raman spectroscopy (FT-SERS) method with different pH and concentrations. According to the experiments, in order to get the best FT-SERS effects, the optimal concentration range of the L-methionine on silver sol is between 10(-3) mol x L(-1)-10(-4)(mol x L(-1). The FT-SERS effects and adsorption model change with pH; The SERS are poor when pH is near the isoelectric point or over 11 or 3. The interaction of L-methionine with Ag nanoparticles is the physical and chemical adsorption by NH3, COO-, S, which could also be effected by pH. From the results and previous reports on this aspect, the general rules of the adsorption model and the orientation of the aliphatic-nonpolar amino acids on silver nanoparticles were speculated, which would be useful for the study of amino acids, protein, peptide, enzyme etc.