Study On Residue Photodegradition Of Chlorothalonil In The Artificial Simulation Of Light Conditions On The Pepper

Methods of photolysis of chlorothalonil on pepper surface were established. The photochemical degradation of chlorothalonil on pepper surface was studied through adding chlorothalonil on pepper surface. The effect of colors, structures of capsicum, fertilizers, kinds of pesticide adjutants（surfactants）on the photolysis of chlorothalonil was studied with HPML and XL as light source.Residues of chlorpyrifos were extracted from pepper with acetonitrile, cleaned up with florist and determined by GC-ECD. The method detection limit (MDL)of chlorpyrifos in the samples of pepper was0.01mg/kg-1.0mg/kg，the average recoveries and coefficient of variations of the method were96%-102%,2.49-3.3%. These results showed that both the methods accorded with demands of residue analysis of pesticides.Several fertilizers affecting the photolysis of chlorothalonil on pepper surface was studied. The photolysis follow the first order kinetics with the high pressure mercury lamp. But the photolysis rates of chlorothalonil were different. The foliar fertilizer and foliar microelement fertilizer showed photo quench effect on the photolysis of chlorothalonil.The photochemical degradation of chlorothalonil on different color of pepper surface with HPML and XL was studied. The dissipation half-life of chlorothalonil on green pepper surface by HPML was1.62h, the red was1.7h, the yellow was2.27h. The dissipation half-life of chlorothalonil on green pepper surface by XL was2.22h, the red was3.88h, the yellow was3.02h. The results showed that the photochemical degradation rate of chlorothalonil with XL was slower than that with HPML.The effect of structures of capsicum on the photolysis of chlorothalonil was studied with HPML. The photodegradation experiment was studied after adding chlorothalonil on peeled pepper. The dissipation half-life of chlorothalonil on green pepper surface by HPML was0.841h, the red was1.16h, the yellow was0.95h. The photodegradation of chlorothalonil on covered the different colors of pepper under peeled the skin with HPML was studied. The dissipation half-life of chlorothalonil on green pepper surface by HPML was3.08h, the red was3.09h, the yellow was3.08h. The double-deck photodegradation of chlorothalonil on covered the different colors of pepper under peeled the skin by HPML was studied. The dissipation half-life of chlorothalonil on green pepper surface by HPML was3.12h, the red was3.11h, the yellow was3.11h. The results showed that the difference between the half-lives of chlorothalonil on three colors of pepper was indistinctive following the different colors of pepper under peeled skin was covered.The effect of kinds of pesticide adjuvant（surfactants）on the photolysis of chlorothalonil on pepper surface was studied. The sodium dodecylbenzene sulfonate (SDBS) and Tween-80enhanced the photodegradation of chlorothalonil. The cetyltrimethyl ammonium bromide (CTAB) showed photo quench effect on the photolysis of chlorothalonil.