黑豆酯酶检测氧乐果残留条件的优化

Optimization of detection conditions of omethoate residues using black soybean esterase

中文关键词:  黑豆  酯酶  氧乐果  检测  响应面法

英文关键词:black soybean  esterase  omethoate  detection  response surface methodology

中文摘要:

      目的 研究以氧乐果为代表的有机磷农药残留检测条件。方法 以黑豆酯酶为酶源, α-乙酸萘酯为底物, 采用酶抑制法, 考察黑豆酯酶稀释倍数、显色时间、反应温度3个因素对黑豆酯酶活力测定的影响。然后通过3因素3水平响应面法优化黑豆酯酶活力的测定条件, 并确定氧乐果对黑豆酯酶的最佳抑制时间和检测的灵敏度。结果 当黑豆酯酶稀释倍数为18, 显色反应时间为10 min, 反应温度为41 ℃时, 黑豆酯酶活力测定的吸光度值达到0.811。氧乐果抑制黑豆酯酶的最佳时间是4 min。绘制氧乐果对黑豆酯酶的标准曲线, 得到最低检测限为0.1 μg/mL。结论 本研究获得了以黑豆酯酶抑制法检测氧乐果残留的最佳条件, 其检测限低于有机磷农药氧乐果残留检测的最低限值要求(0.2 μg/mL)。因此, 以黑豆酯酶为酶源的酶抑制法可以作为有机磷农药氧乐果残留快速检测的一种有效手段。

英文摘要:

      Objective To discuss detection conditions of omethoate residue, which is one of the most frequently-used organophosphorus pesticides. Methods Enzymatic inhibition method was applied and black soybean esterase was chosen as enzymatic resource, and α-naphthyl acetate as the substrate. Effects of dilution ratio of black soybean esterase, reaction time and reaction temperature on the determination of black soybean esterase activity were studied. Then optimum determination conditions, including the optimal inhibition period and detection sensitivity, were obtained by three-factor and three-level response surface methodology. Results The best condition was as follows: dilution ratio was 18 times, reaction time was 10 min and reaction temperature was 41℃. Under these conditions, the optimum absolution density reached 0.811. The optimal inhibition period was 4 min. Standard curve of inhibition of omethoate to black soybeans esterase was ploted, and the lowest detection limit was 0.1 μg/mL, which was lower than the limit value of detection standard for organophosphorus pesticides residues. Conclusion The optimal detection conditions of omethoate residues for black soybean esterase were obtained, and the detection limit was lower than that (0.2 μg/mL) of organophosphorus pesticide residues detection requirements. The enzyme inhibition method based on black soybean esterase can be an effective method of rapid detection for organophosphorus pesticides residues since its lowest detection limit meets the threshold limit value requirement.