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利用炭气凝胶(CAs)修饰硼掺杂金刚石(BDD)电极对甲基对硫磷进行检测。1.0×10-4mol/L甲基对硫磷在裸BDD电极和CAs-BDD电极上的差分脉冲伏安结果表明,经CAs修饰后,峰电流从4.576μA增加到10.43μA,峰电位从-0.644 V移至-0.556 V,说明CAs具有较高的电催化活性,可促进电极表面的电子转移,加快反应速率。研究了不同pH的缓冲液和修饰量对电极响应的影响,实验得出最佳缓冲液pH=6.8,最佳修饰量为5μL。在最优条件下,甲基对硫磷的浓度与其峰电流在4～200μmol/L范围内呈线性关系,线性方程为I p=-0.03222 c-2.09172(r2=0.9979),检出限为1.188μmol/L。采用本方法对实际样品中的甲基对硫磷的含量进行测定,平均回收率为98.4%～106.6%之间。
Methyl parathion was detected by carbon airgel (CAs) modified boron doped diamond (BDD) electrode. Differential pulse voltammetry of 1.0 × 10-4 mol / L methyl parathion on bare BDD electrode and CAs-BDD electrode showed that after CAs modification, the peak current increased from 4.576μA to 10.43μA and the peak potential increased from -0.644 V to -0.556 V, indicating that CAs have a high electrocatalytic activity, can promote the electrode surface electron transfer and speed up the reaction rate. The effects of different pH buffers and amount of modification on the electrode response were studied. The optimum pH of the buffer solution was found to be 6.8, and the optimal amount of modification was 5μL. Under optimal conditions, the concentration of methyl parathion and its peak current in the range of 4 ~ 200μmol / L showed a linear relationship, the linear equation was I p = -0.03222 c-2.09172 (r2 = 0.9979) with a detection limit of 1.188 μmol / L. The content of methyl parathion in the actual sample was determined by this method. The average recoveries ranged from 98.4% to 106.6%.