AuCo合金微粒-石墨烯复合膜修饰电极的制备及其在测定亚硫酸根中的应用

Preparation of AuCo Alloy Particles-Graphene Composite Film Modified Electrode and Its Application in Determination of Sulfite

以石墨烯（GN）修饰玻碳电极（GCE）为基底,以HAuCl4,Co（NO3）2,Na2SO4及十二烷基磺酸钠（SDS）的混合溶液为电沉积液,在-1.0 V（vs.SCE）恒电位沉积制备出新型AuCo合金微粒修饰电极（AuCo/GN/GCE）.所得AuCo微粒呈球形带刺状,均匀分布在石墨烯表面.它对SO32-的电氧化表现出催化作用,在酸性溶液中SO32-可在AuCo/GN/GCE上产生灵敏的氧化峰.在优化后的实验条件下,AuCo/GN/GCE在0.4V对SO32-的响应电流与其浓度在0.5～28 μmol/L和36～ 324 μmol/L范围内呈线性关系,检出限为0.2μmol/L（S/N=3）.该电极具有良好的重现性和稳定性,将其用于饮品中SO32-的电化学测定,加标回收率为94％～109％.

AuCo particles were electrodeposited on a graphene （GN） coated glassy carbon electrode （GCE） at -1.0 V （vs. SCE） from 1 mmol/L HAuC14＋ 20 mmol/L Co（NO3）2＋ 0.2 mol/L Na2SO4＋ 0.04 mmol/L sodium dodecyl sulfonate solution. The obtained AuCo particles showed spherical shape with thorns and they were well distributed on the GN surface. The AuCo alloy particles presented catalysis to the electrochemical oxidation of sulfite that could produce a sensitive anodic peak at the resulting AuCo/GN/GCE electrode in H2SO4 solution. Under the optimized conditions the response current of the electrode at 0.4 V and the sulfite concentration presented linear relationship over the ranges of 0.5- 28 μmol/L and 36- 324 μmol/L. The detection limit was 0. 2 μmol/L （ S/N = 3 ）. The modified electrode also displayed good stability and reproducibility. When it was applied to the determination of sulfite in drink samples the recovery for standard addition was 94% - 109%.