基于MnO2纳米片类氧化酶特性的有机磷农药荧光分析方法建立

Development of a Fluorescence Method for Detection of Organophosphorus Pesticides Based on Oxidase-mimicking Activity of MnO Nanosheets

利用MnO2纳米片类氧化酶特性并结合有机磷农药的酶抑制原理,构建一种快速、简便、高灵敏有机磷农药荧光分析方法。通过测定反应体系荧光强度前后的变化,可以检测样品中有机磷农药的含量。通过优化酶浓度、底物浓度和反应时间,发现乙酰胆碱酯酶浓度为9.375 U/L,底物浓度为10 mmol/L,反应时间为11 min时,该荧光分析方法检测性能最佳,对氧磷的动态检测范围为1.56~200 ng/mL,检出限达到0.5 ng/mL(RSN=3),运用该方法测定标准添加的自来水、卷心菜、燕麦样品的回收率在83.4%~105.9%之间,表明该方法具有很高的灵敏度与准确性,为快速高灵敏测定有机磷农药提供一种新的可能。

In this study, a rapid, simple and highly sensitive fluorescence method for the detection of organophosphorus pesticides was developed based on the oxidase-like activity of manganese dioxide nanosheets and the principle of enzymatic inhibition of organophosphorus pesticides. The contents of organophosphorus pesticides in samples was determined by measuring the change in the fluorescence intensity of the reaction system. An acetylcholinesterase(AChE) concentration of 9.375 U/L, a substrate concentration of 10 mmol/L and a reaction time of 11 minutes were found to be the optimal conditions to achieve the best detection performance. The dynamic detection range of paraoxon was 1.56–200 ng/mL, and the limit of detection(LOD) was 0.5 ng/mL(RSN = 3). The recoveries from tap water, cabbage and oat samples spiked with varying concentrations of paraoxon were in the range of 83.4%–105.9%. These results indicated that this method had several remarkable advantages including rapidity, and high sensitivity and accuracy.