The Analysis And Research Of Several Pesticide Residues In Postharvest Apple

In this paper, the research was studied with adopting field experiments.,we selected insecticides(phoxime and cyhalothrin) and germicides (chlorothalonil and carbendazim) respectively, and adopt different concentrations and interval periods before harvested products,we researched the final residuces in apple and evaluated degradation dynamics,safety during its cold storage(T:0±1℃;RH:90%).simultaneously,we established a rapid method for pesticide residues in apple and hope to offer scientific foundation.The results indicated that:1. Objective to establish a rapid method for simultaneous determination of cyhalothrin and chlorothalonil residues in apple. The aimed residues were extracted from apples with acetonitrile and cleaned up with Florosil columns, are analyzed with Finnigan Trace GC the recoveries of the pesticides from apple were between 70.0% and 110.0%,RSD were less than 10%, The method is simple,sensitve,rapid,and is applied to detect cyhalothrin and chlorothalonil pesticide residues in apple.2.We adopt recommend and double concentration on the all experiments,The present research results showed the residues of phoxime is the lowest.0.021mg/kg and 0.026mg/kg in gala and Fuji respectively,which are lower than the limited target 0.05mg/kg at 10 days before being harvested. the residues of carbendazim is hightest,0.198mg/kg and 0.297mg/kg and still lower the limited target 0.05mg/kg。10 days before being harvested.the residues of skin was 0.687mg/kg. the residues of cyhalothrin and chlorothalonil were middle, and reachered 0.035mg/kg,0.079mg/kg,0.067mg/kg,and0.078mg/kg respectively.3.Through the test of degradation trend of four kinds of pesticides,we obtain the degradation equations during storage.The degradation equation of phoxime in gala and Fuji are Y=0.023e^-0.0689x R2=0.9047, The half life (T/2) is 10.1d,Y=0.0276e^-0.0495x R2=0.9179, T/2 is 14.0d. The rate of degradation has no obvious difference in different varieties.The degradation equation of cyhalothrin in gala and Fuji are Y=0.064e^-0.0989x R2=0.8485, The half life (T/2) is 7.0d and Y=0.1226e^-0.0495x R2=0.9137, T/2 is 7.0d. The rate of degradation has no obvious difference in different varieties.The degradation equation of chlorothalonil in gala and Fuji are Y=0.0765e^-01224x R2=0.8921,T/2 is 5.7d , Y=0.2043e^-0.0807x,R2=0.8295,T/2 is 8.5d,Y=0.051e-^0.1039x, R2=0.8349,T/2 is 6.7d,The rate of degradation has no obvious difference in different varieties.The degradation equation of carbendazim in gala and Fuji areY=0.4498e-0.1447x R2=0.9001,T/2 is 4.8d,Y=0.7016e-^0.1608x,R2=0.9303,T/2 is 4.3d,The rate of degradation has no obvious difference in different varieties.4.After spray pesticide,the residues order in different position of apple is:peel>apple>pulp,and the residue in peel position is far over than pulp,pesticide main remain in peel position of apple,the pulp position remains relatively low. During harvested time,the residuce of phoxime in the pulp position is 1.80 times than fruit in gala and 1.65 times in Fuji.the residuce of cyhalothrin in the pulp position is 1.59 times than fruit in gala and 2.29 times in Fuji.the residuce of chlorothalonil in the pulp position is 4.18 times than fruit in gala and 4.32 times in Fuji.the residuce of carbendazim in the pulp position is 4.18 times than fruit in gala and 7.0 times in Fuji.