层层自组装复合电极用于检测牛奶中三聚氰胺

Layer-by-Layer Self-Assembly Modified Electrodes for Detection of Melamine in Milk Samples

研制一种新型、简单、低成本的电化学传感方法,用于检测乳品中的三聚氰胺.首先将氧化石墨烯涂到电极上,制备GO/GCE修饰电极;然后利用层层自组装方法,把1,4-二硫苏糖醇(DTT)、金纳米粒子、L-半胱氨酸(L-Cys)组装到修饰电极表面,制备了GO/DTT/AuNPs/L-Cys/GCE复合电极,用来检测三聚氰胺.通过电化学阻抗和循环伏安行为探讨该修饰电极检测三聚氰胺的作用机理,同时优化了实验条件.该复合电极检测范围在1. 0×10^(-7)～1. 0×10^(-3)mol/L内呈良好线性关系,最低检测浓度为1. 0×10^(-8)mol/L.该修饰电极选择性和重现性好,用于牛奶样品中三聚氰胺的检测,回收率为98. 3%～99. 95%,有实际应用价值.

A new, simple and low-cost electrochemical sensor was prepared to detect melamine in dairy products. A GO/DTT/AuNPs/L-Cys/GCE electrode was developed for detection of melamine in milk samples. The modified electrode was obtained by layer-by-layer self-assembly methods using 1,4 dithiothreitol （DTT）, gold nanoparticles and L-cysteine （L-Cys） on GO/GCE. The mechanism of the modified electrode to detect melamine was discussed by electrochemical impedance and cyclic voltammetry, and the experimental conditions were optimized. Under the optimized condition, the peak current of melamine was linear ranging from 1.0 × 10 -7 to 1.0 × 10 -3 mol/L. The detection limit was 1.0 × 10 -8 mol/L for melamine. The proposed method was further successfully when it applied to the determination of melamine in milk samples, and the results showed good stability and high reproducibility. The proposed electrode can be well applied to the determination of naelamine in milk samples with a recovery rate of 98. 3 % ～ 99. 95 %, showing its potential application prospect.