增强氯化血红素催化活性用于水胺硫磷比色检测研究

建立了一种基于增强氯化血红素(Hemin)过氧化物酶催化活性比色检测水胺硫磷的方法.在H2O2存在下, Hemin催化氧化底物3,3′,5,5′-四甲基联苯胺(TMB), 使其失去1个电子, 导致反应体系由无色变为蓝绿色.水胺硫磷的加入可提高Hemin对底物亲和力, 进一步增强其催化活性, 使底物氧化失去2个电子, 反应体系由蓝绿色变为黄色, 且颜色变化程度与水胺硫磷浓度成正比.在最优条件下, 本方法的动态检测范围为2～100 μg/L, 检出限为1.2 μg/L(3σ).其它有机磷农药对水胺硫磷检测无明显干扰, 实际样品中水胺硫磷的加标回收率为93.0％～113.0％. 本方法可应用于农产品中水胺硫磷残留的检测.

Colorimetric Determination of Isocarbophos Based on Enhanced Peroxidase-like Activity of Hemin

A simple colorimetric method for detection of isocarbophos was developed based on the enhanced peroxidase-like activity of hemin. Hemin could catalyze the oxidation of peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) by H2O2, which made TMB to lose one electron and caused reaction solution color changing from initial transparent to blue-green. Adding isocarbophos improved hemin affinity to substrates, which further enhanced peroxidase-like activity of hemin and made TMB to lose two electrons. The color of TMB solution was further changed from blue-green to yellow, and the degree of color change was proportional to the concentration of isocarbophos. Under the optimal conditions, the present analytical method for isocarbophos detection had a dynamic range from 2 μg/L to 100 μg/L with a detection limit of 1.2 μg/L (3σ). The selectivity assay demonstrated that other organophosphorus pesticides exhibited negligible interferences for isocarbophos detection. The application of the proposed method in the practical samples showed that the mean recovery of isocarbophos was in the range of 94.4％-113.0％, thus it could be widely applied to rapidly and sensitively detect isocarbophos in the agricultural products.