儿茶素对丙溴磷及其代谢物的光降解作用研究

Study on the photodegradation of catechins to profenofos and its metabolites in water

为研究丙溴磷在水中的光降解以及儿茶素对丙溴磷光降解的影响,利用高压汞灯为光源研究了不同浓度儿茶素对丙溴磷和主要降解产物的光降解作用。结果发现,在高压汞灯照射下,浓度为5μmol·L^(-1)的丙溴磷在超纯水中的降解半衰期为0.125 h,当添加摩尔比为1∶1、1∶5、1∶10和1∶20的儿茶素后,半衰期分别为0.134、0.148、0.170和0.204 h,半衰期分别延长了1.01、1.18、1.36和1.63倍,说明儿茶素能够抑制水溶液中的丙溴磷光降解,且儿茶素添加剂量越大抑制作用越强;儿茶素能清除水中的羟基自由基从而抑制丙溴磷的光降解;丙溴磷的光降解产物主要为2-氯-4-溴苯酚和O-(2-氯苯基)-O-乙基-S-丙基-硫代磷酸酯;O-(2-氯-苯基)-O-乙-S-丙基硫代磷酸酯和2-氯-4-溴苯酚在高压汞灯的降解半衰期分别为25.21和3.71 min;添加儿茶素后,O-(2-氯-苯基)-O-乙-S-丙基硫代磷酸酯和2-氯-4-溴苯酚的半衰期分别为69.24和15.67 min,半衰期分别延长了2.75和4.22倍;相同浓度的儿茶素对2-氯-4-溴苯酚的光降解抑制效果强于丙溴磷和O-(2-氯-苯基)-O-乙基-S-丙基硫代磷酸酯。研究结果有助于探究丙溴磷在自然环境中的光降解机制效应,为丙溴磷潜在的环境风险提供了一定的依据。

In order to study the photodegradation of profenofos and the effect of catechins on the photodegrada-tion of profenofos in water,the photodegradation of profenofos and the main degradation products by catechins at dif-ferent concentrations were studied under high pressure mercury lamp(HPML)using high performance liquid chro-matography.The result showed that the degradation half-life of profenofos was 0.125 h in water at a concentration of 0.5μmol·L^(-1) under HPML irradiation,while the half-lives of profenofos were 0.134,0.148,0.170 and 0.204 h in the presence of 1,5,10 and 20 molar ratio of catechins,respectively,the half-lives were increased 1.01,1.18,1.36 and 1.63 times,respectively,which indicated that catechins inhibited the photodegradation of profennofos in aqueous solu-tion,and the effect increased as the concentration increased;catechin could eliminate hydroxyl radicals in water and inhibit photodegradation of profenofos;the photodegradation products of profennofos were main 2-chloro-4-bromo-phenol and O-(2-chlorophenyl)-O-ethyl-S-propyl-thiophosphate.The half-lives of 2-chloro-4-bromophenol and O-(2-chlorophenyl)-O-ethyl-S-propyl-thiophosphate were 25.21 and 3.71 min,respectively,while those were 69.24 min 15.67 min with catechins,respectively,and the half-lives were increased 2.75 and 4.22 times.Catechins had greater inhibitory effect on photodegradation of 2-chloro-4-bromophenol than that of O-(2-chlorophenyl)-O-ethyl-S-propylthiophosphate and profenofos.The results are helpful to study the photodegradation of profenofos in the natural environment,and provide a certain basis for the potential environmental risks of profenofos.