丁香菌酯在水中的光解影响因素研究

Study on influencing factors of photochemical degradation of coumoxystrobin in buffer solutions

为了更好地了解丁香菌酯(coumoxystrobin)在环境中的归趋,基于《化学农药环境安全评价试验准则》推荐方法,采用高效液相色谱(HPLC)分析方法研究了光源(500 W氙灯和20 W汞灯)、初始质量浓度(1、5、10和15 mg/L)、pH值(4、7和9)和添加助溶剂吐温80对丁香菌酯在水中光解的影响。结果表明:在试验条件下,丁香菌酯的光解反应均符合准一级反应动力学方程;在500 W氙灯和20 W汞灯两种光源条件下,其半衰期分别为2.23和1.10 h,20 W汞灯下的光解速率约为500 W氙灯下的2倍;在同一光源下,光解速率随丁香菌酯初始质量浓度的增加而降低,二者呈负相关关系;丁香菌酯在pH值不同的3种缓冲溶液中的光解速率从大到小依次为pH 9、pH 4和pH 7;吐温80对丁香菌酯的光解有抑制作用。该研究结果可为丁香菌酯的合理使用及环境评价提供参考。

In order to better comprehend the fate of coumoxystrobin in the environment,the photolysis of coumoxystrobin under different light sources(500 W xenon lamp and 20 W mercury lamp),initial concentrations(1,5,10,and 15 mg/L)and pH values(4,7 and 9)were investigated based on the method recommended by China Test Guidelines on Chemical Pesticide Environmental Safety Assessment via high-performance liquid chromatography.The results demonstrated that the photolysis of coumoxystrobin under the experimental conditions matched quasi first-order kinetic equation.The photolysis half-lives under 500 W xenon lamp and 20 W mercury lamp were 2.23 and 1.10 h,respectively.The photolysis rate of 20 W mercury lamp was about twice that of 500 W xenon lamp.Under the same irradiation conditions,the photolysis rate decreased with the increasing initial concentrations,which were negatively correlated.The photolysis rate of coumoxystrobin in the three buffer solutions showed as follows:pH 9>pH 4>pH 7.Tween 80 could inhibit the photolysis of coumoxystrobin.The study provide references for the rational use and environmental assessment of coumoxystrobin.