溶液酸碱性对异构体氨基酸单分子膜影响的表面增强拉曼光谱研究

SERS Study with Effect of Solution pH on Self-assembled Monolayers of Leucine and Isoleucine Modified on Silver

利用表面增强拉曼(SERS)光谱技术研究比较了在粗糙化银电极表面吸附的亮氨酸与异亮氨酸自组装单层膜结构以及溶液酸碱性对分子吸附作用的影响。研究表明在粗糙化银电极表面两种氨基酸分子主要是以COO-为作用位点进行吸附的。进一步的研究也揭示溶液pH值的变化没有显著改变两种氨基酸分子在银电极表面以去质子化羧基吸附为主的特征,但对于羧基吸附作用的影响程度及其变化规律是迥异的,对氨基的影响也有一定的差异。

In this research,surface-enhanced Raman scattering（SERS） technique was used to investigate the characteristics of conformation and surface property of leucine and isoleucine self-assembled monolayers（SAMs） adsorbed at roughened silver surface when the pH value of the solution was changed.The results reveal that leucine and isoleucine molecules are adsorbed mainly via the deprotonated carboxyl groups at roughened silver electrode.This feature was not changed significantly with variation of solution pH,but the effects of solution pH on the interaction between carboxyl groups from leucine or isoleucine molecules and silver substrate are different from each other,and so are for the amino groups.