L-半胱氨酸自组装膜电极对硒的电催化及分析应用

The Electrocatalytic Effect of the Self-assembled L-Cysteine-Modified Gold Electrode on Selenium?and Its Analytical Application

利用L 半胱氨酸自组装膜修饰金电极 (L CysAu/SAMs) ,用于含Se 溶液的测定。在 0 .1mol/LH2 SO4介质中 ,经 - 0 .30V(vs.SCE)富集 3min后 ,在 0 .0～ 1 .3V范围内 ,进行循环伏安扫描 ,发现该修饰电极对Se 的氧化还原较裸金电极有明显的电催化作用。探讨了其电化学行为 ,选用Se 在 0 .80V处的氧化峰为分析信号 ,以 1 .5次微分线性扫描伏安法对硒进行定量分析 ,线性范围为 1 .0× 1 0 -8～ 1 .0× 1 0 -6mol/L ,检出限为 1 .0× 1 0 -9mol/L。所建立的方法用于北芪样品中痕量硒的测定 ,获得满意的结果。

The electrochemical behaviors of selenium? on the self assembled monolayer L cysteine modified gold electrode L cys/Au SAMS were studied in 0.1 mol/L H 2SO 4 solution after enriching for 3 minutes at -0.30 V( vs .SCE) and scanning at the potential range of +0.0～+1.3 V by the cyclic voltammetry. It showed that Se? on L cys/Au SAMs had an obvious electrocatalytic effect ,which is superior to the gold electrode without modified , and its electrochemical mechanism was studied . The oxidation peak of Se? at +0 80 V was used in the determination of Se?. This method has a good linear relation in the concentration range of 1 0×10 -8 ～1.0×10 -6 mol/L and its detection limit is 1.0×10 -9 mol/L . The method was used to determine the concentration of Se? in astragali samples. The result from the method was coincided with that of the fluorescence spectrometry.