氯化亚锡吸附与配位作用下L-肌肽的表面增强拉曼光谱

利用在电极表面强化学吸附的氯化亚锡与被测有机/生物分子之间的相互作用,不仅可以有效消除被测分子的碳化和氧化现象,还可以获得特别的增强信号,可应用于反应活性强的有机/生物分子的表面增强拉曼光谱分析。还报道了肌肽的电化学表面增强拉曼散射(SERS)光谱的研究结果,重点考察了加入氯化亚锡前后和改变电极电势对肌肽吸附SERS光谱的影响。无氯化亚锡时,肌肽的SERS光谱存在严重的碳化信号的干扰;氯化亚锡存在下,调控电极电势可引起吸附的氯化亚锡与肌肽在电极表面发生配位作用,借助这种表面相互作用,可将肌肽固载于基底表面,从而获得L-肌肽的高质量表面增强拉曼光谱,完全消除碳化现象的干扰。

SERS Spectra of L-Carnosine under the Interaction of Coordination with Adsorbed SnCl_2

The authors have found that by virtue of utilizing the interaction of strongly chemically adsorbed SnCl_2 with the ana-lytes of organic/biologic molecules, the authors can not only effectively eliminate the laser carbonization and oxidation of probe molecules (e. g. pyridine), but also obtain specially enhanced Raman signals (e. g. vitamin B_6). This method is applicable to the SERS spectroscopic analysis of highly reactive organic/biologic molecules. In the present paper, the authors report the investiga-tion results on the electrochemical SERS spectra of L-carnosine (LCar) for the first time, mainly concentrating on the influence of adsorbed SnCl_2 and applied potential on the SERS spectra of LCar. The SERS spectra of LCar were badly interfered by laser carbonization in the absence of SnCl_2. However, in the presence of SnCl_2 high quality SERS spectra of LCar could be obtained free of carbonization. It is demonstrated that LCar can be immobilized on the gold substrate indirectly via surface coordination with the pre-adsorbed SnCl_2 under potential control. Apparently, such a sandwich-like adsorption configuration as Au-Sn(Ⅱ)-ICar is beneficial both to sensing the strong electromagnetic field at the nanostructured gold surface and to preventing the from damage by the laser.