茜素红S-壳聚糖结合反应的电化学研究

Electrochemical Study on the Binding Reaction Between Alizarin Red S and Chitosan

在pH4．5的Britton-Robinson缓冲溶液中，茜素红S(ARS)可以与壳聚糖(CTS)发生结合反应形成一种非电活性的超分子复合物。用线性扫描二阶导数极谱法对结合反应体系进行了研究，结果表明，该复合物的形成使溶液中游离的ARS浓度降低，进而导致ARS的还原峰电流降低。优化了结合反应的最佳条件和电化学测定条件：pH=4．5，B-R用量2．5mL，温度<35℃，时间10min，ARS浓度5．0×10^-5mol·L^-1，扫速800mV·s^-1。在此条件下，峰电流的降低同CTS的浓度在一定范围内呈良好的线性关系，用于CTS的检测，线性范围为0．80～50．0mg·L^-1，线性回归方程为△ip″(nA)=493．09+108．24c(mg·L^-1)(γ=0．997，n=20)，对结合反应机理进行了初步的探讨。

An electrochemical study on the interaction between Alizarin Red S (ARS) and chitosan (CTS) using a mercury electrode in pH 4. 5 Britton-Robinson (B-R) buffer solution was described. ARS has a well-defined second order derivative linear-sweep po-larographic wave at - 0. 39 V. Adding CTS to the ARS solution resulted in the decrease of the peak current without the change of peak potential, which indicated that an elec-trochemically inactive complex was formed and the concentration of ARS in solution decreased. The conditions of binding reaction and electrochemical detection were optimized. Under the optimum conditions, the ip' of ARS decreased in proportion to the CTS concentration from 0. 80 - 50. 0 mg · L-1 with the linear regression equation of △iP'(nA) =493. 09+108. 24 c(mg · L-1 ) (γ = 0. 997, n = 20). The binding reaction mechanisms of ARS-CTS were preliminary discussed.