吡唑萘菌胺在土壤中的降解特性

Degradation characteristics of isopyrazam in soil

[目的]明确吡唑萘菌胺在土壤中的降解规律,为其在环境中的归趋提供理论支持。[方法]建立了基于QuEChERS前处理技术结合HPLC-MS/MS检测土壤中吡唑萘菌胺残留量的方法,样品经5 mL水、10 mL乙腈提取,50 mg C_(18)净化,通过室内模拟试验,探究了土壤类型和不同因素对吡唑萘菌胺在土壤中降解的影响。[结果]吡唑萘菌胺在土壤中残留检测方法平均回收率在94.79%~109.59%之间,在不同土壤中的降解符合一级动力学方程,在4种土壤中的降解速率为黑土>水稻土>潮土>红土;土壤湿度越大,其在土壤中降解速率越快;吡唑萘菌胺在厌氧条件下降解速率高于好氧条件,厌氧和好氧条件下的半衰期分别为68.76、112.89 d;土壤灭菌和去有机质延长了其在土壤中的半衰期。[结论]试验所建立的方法适用于检测吡唑萘菌胺在土壤中的残留,土壤类型、含水量、土壤灭菌和去有机质均可影响其在土壤中的降解,土壤有机质含量是影响吡唑萘菌胺在土壤中降解的主要因素。

[Aims]This study aims to clarify the degradation regularity of isopyrazam in soil and provide theoretical support for its fate in the environment.[Methods]A method was established based on QuEChERS pretreatment technology combined with HPLC-MS/MS to determinate the residue of isopyrazam in soil.The samples were extracted with 5 mL of pure water and 10 mL of acetonitrile,and purified by 50 mg of C18.Through laboratory simulative experiments,the effects of soil type and different factors on the degradation of isopyrazam were explored.[Results]The average recovery rate of the method was between 94.79%and 109.59%,the degradation of isopyrazam in different kinds of soil conformed to the first-order kinetic equation,and the degradation rates in 4 kinds of soil were as follows:black soil>paddy soil>aquid soil>red soil.The higher the soil moisture content,the faster the degradation rate;the degradation rate of isopyrazam under anaerobic conditions was higher than that under aerobic conditions,and its half-lives under anaerobic and aerobic conditions were 68.76 and 112.89 d,respectively.Soil sterilization and deorganicism extended its half-life in the soil.[Conclusions]The method established in the test is suitable for detecting the residue of isopyrazam in soil.Soil type,water content,soil sterilization and deorganicism can all affect its degradation in soil,among which soil organic matter content is the main factor affecting the degradation of isopyrazam in soil.