The degradation of oxadiazon and oxyfluorfen by photolysis

The photodegradation of two herbicides oxadiazon and oxyfluorfen on soil an d in water has been studied. Photolysis of each herbicide was conducted on soil TLC plates and also in Milli-Q water using borosilicate flasks. Photop roducts were isolated from the water using C-18 cartridges. Identification of the photoproducts from each herbicide was made using CC-MS. Three photop roducts were isolated following irradiation of oxadiazon and the fragmentat ion pattern indicated loss of chlorine was the dominant process. In the cas e of oxyfluorfen the photoproducts found showed the loss of the nitro group , dechlorination and cyclisation were the predominant processes during phot olysis. The half-lives of each herbicide were significantly shorter in wate r than on soil.