菠菜中乐果农药残留的比色法测定条件研究

为研究菠菜中乐果农药残留的快速安全检测方法,根据乐果在碱性（NaOH）溶液中分解,生成物Na2S和亚硝酰铁氰化钠反应生成洋红色产物的原理,对比色条件进行了研究和优化.详细分析并验证了显色体系的配制方法,确定了显色体系的较佳参数值：pH值为5.7,温度为24℃,反应时间为20 s.实验结果表明,最佳比色条件下在390 nm处有明显的特征吸收峰,可以测定1×10-6的乐果农药残留.用最小二乘法建立了菠菜中乐果农药残留的数学模型,相关系数R2=0.941 5,样品回收率为91.6％～108.9％,为以后开发便携式农药残留检测仪器的光源提供了依据.

Study on Colorimetry Determination Conditions of Rogor Pesticide Residues in Spinage

In order to research the fast and safe determination method of Rogor pesticide residues in spin- age, the colorimetric reaction conditions were researched and optimized in this study according to the principle that Nitrosyl iron sodium cyanide can produce carmine product by reacting with NazS produced from the reaction between Rogor and NaOH solution. The experiment results showed that under the opti- mum coloring conditions 1 × 10-6 Rogor pesticide could be detected at 390 nm absorption wavelength. The configuration method of the colorimetric system was analyzed and the optimum conditions were pH 5.7, suitable coloration temperature 24 ℃ , and reaction time 20 s. The mathematical model was built by the least square method. The correlation coefficient was 0. 941 5 and the sample recovery percent was 91.6% - 108.9% , which provide the feasible basis for developing light source of portable pesticide resi- dues detecting instrument.