金纳米颗粒作为Cu^(2+)氧化半胱氨酸的可视化指示剂及其应用

Gold Nanoparticles as a Visual Indicator for Redox Reaction Between Copper Ion and Cysteine and Its Analytical Application

Cu2+能选择性氧化半胱氨酸,破坏半胱氨酸与金纳米颗粒之间金硫键的形成,阻止半胱氨酸导致的金纳米颗粒聚集。因而,金纳米颗粒可作为Cu2+氧化半胱氨酸的可视化指示剂,本实验据此建立了高选择性检测Cu2+的色度分析方法。在HCl-NaAc缓冲体系(pH 3.6)中,金纳米颗粒在525 nm处的吸光度值与Cu2+的浓度在8.0×10-8~2.0×10-6mol/L范围内呈良好的线性关系,相关系数为0.9962;检出限(3σ/k)为1.5×10-9mol/L。将本方法用于天然水体中Cu2+的测定,具有较好的精密度和准确度。

A colorimetric method for copper ion （Cu^2＋ ） in aqueous solution is described on the basis of the oxidation of thiol group of cysteine by Cu^2＋ , which depends on the binding of eysteine-AuNPs and with the damage of binding, the formation of gold nanoparticle aggregates would be restrained. Thereby AuNPs acts as the visualization indicator for the oxidation of cysteine by copper ions. In a medium of pH 3.6, a linear relationship has been obtained between the absorbance at 525 nm and the concentration of Cu^2＋ in the range of 8.0×10^-8-2.0×10^6 mol/L with the correlation coefficient （r） of 0. 9962 and the detection limit （3σ/k） of 1.5×10 9 mol/L. The proposed method has been successfully applied to the analysis of synthetic mixtures and water samples.