Study on the photodegradation of catechins to profenofos and its metabolites in water
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 0.5 μmol·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.
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维普
