Studies On Residue Analysis Method And Dissipation Dynamics Of Forchlorfenuron

This paper firstly reported the residual determination method and dissipationdynamic of Forchlorfenuron in cucumber,grape and soil in China.The samples were extracted with mixture of acetone: dichloromethane(2:1, v/v),cleaned up by passing through a C18 column, and determined by capillary gaschromatography with ECD. The minimum amount of detection was 3×10^-11g, and theminimum concentration of detection in cucumber and grape were 0.001mg·kg^-1, and insoil was 0.002mg·kg^-1, The average recoveries of Forchlorfenuron in cucumber were80.18%～110.75%, in grape were 89.51%～110.91%, in soil were 85.01%～111.52%,respectively. The coefficients of variation ranged were 6.59%～10.26% in cucumber,6.32%～7.37% in grape and 4.64%～10.68% in soil.Residual trial of Forchlorfenuron were conducted in Beijing Tongzhou, ShandongJinan, Zhejiang Hangzhou and Hunan Changsha in 2005. The result showed:Cucumber plant were treated with the concentration of 30mg·kg^-1 one time during thegrowing season of cucumber, the half-life of Forchlorfenuron were 1.45～2.13 days incucumber. With the concentration of 20mg·kg^-1 and 30mg·kg^-1 treated in cucumber, thefinal residues were 0.002mg·kg^-1 in Hangzhou on the 14 days after treatment, but notdetected in other three regions.Grape plant were treated with the concentration of 30mg·kg^-1 one time during thegrowing season of grape, the half-life of Forchlorfenuron were 4.09～6.01 days in grape.With the concentration of 20mg·kg^-1 and 30mg·kg^-1 treated in grape, the final residues ingrape were 0.006mg·kg^-1 and 0.010mg·kg^-1 in Jinan on 21 days after treatment, and theresidues were not detected in Changsha on the 48 days after treatment; then the residueswere not detected in Hangzhou on the 42 days after treatment; the residues were notdetected in Beijing on the 68 days after treatment.With the concentrate of 50mg·kg^-1 treated in soil one time, the half-life ofForchlorfenuron were 9.03～13.92 days in soil. With the concentration of 20mg·kg^-1 and30mg·kg^-1 treated in cucumber and grape, the residues were not detected in soil from thefield of cucumber and grape in four regions.The dissipation kinetics of Forchlorfenuron in cucumber,grape and soil accord withthe first-degree reaction pattern. There are no MRL of Forchlorfenuron in cucumber andgrape been established in China. Based on the results of this study and refer to othercountry's MRL, the dosage of 10mg·kg^-1-20mg·kg^-1 are suggested to be used on cucumber, and the maximum treatment is one time during the cucumber growing period.The recommended MRL of Forchlorfenuron in cucumber is 0.3mg·kg^-1. Therecommendted dosage of Forchlorfenuron applied on grape are 10mg·kg^-1-2Omg·kg^-1and the maximum treatment is one time during the grape growing period. Therecommended MRL of Forchlorfenuron in grape is 0.1mg·kg^-1...