Residue And Degradation Of Fluazinam In Pepper And Potato

A residual analytical method of Fluazinam in pepper and potato were established in this paper, and the residual behavior of Fluazinam in pepper and potato were studied in field.And the suggestion of reasonable utilization and maximum residue limit standard were proposed.The samples were extracted by acetone,cleaned up by solid phase extraction column of Florisil,and determined by gas chromatography with electron capture detector(ECD).The minimum detectable limit of the instrument was 0.2×10¹⁰ g,and the minumun detectable concentration of Fluazinam in soil,pepper,potato and potato seedling was all 0.002 mg/kg.In the three level of 0.10 mg/kg,0.50 mg/kg and 1.00 mg/kg,the average recoveries in soil,pepper,potato, potato seedling were 85.3～90.3%,78.9～94.1%,79.2～95.3%,89.0～93.2%,respectively,and the relative standard deviations were 2.0～3.9%,1.6～7.6%,2.0～4.2%,2.5～5.5,respectively. Obviously,it was a suitable method to determine the residue of Fluazinam in pepper and in potato.The field trials of Fluazinam in pepper were conducted in two experimental fields located in Zhejiang and Henan provinces respectively.It was demonstrated from the results that the degradation dynamics of Fluazinam in pepper and soil of cultivating pepper accorded with the kinetic equation,and the relativity was good.The half life of Fluazinam in pepper were 2.6～2.7 d and 2.4～2.7 d,and that in soil were 3.4～5.7 d and 3.7～4.6 d in Zhejiang and Henan respectively. When the pepper was treated for four times,on the 7^th day after the last application,the final residue of Fluazinam in pepper was below 0.06 mg/kg,and lower than the MRL in Korea(0.3 mg/kg).The results suggested that Fluazinam 50%SC be used in pepper at most four timse at a dose of 25～33 mL/mu with a safe interval of 7 days from harvest.The field trials of Fluazinam in potato were conducted in two experimental fields located in Heilongjiang and Yunnan provinces respectively.It was demonstrated from the results that the degradation dynamics of Fluazinam in potato and soil of cultivating potato accorded with the kinetic equation,and the relativity was good.The half life of Fluazinam in potato were 3.4～4.7 d and 4.1～5.2 d,and that in soil were 9.5～10.9 d and 8.4～9.5 d in Heilongjiang and Yunnan respectively. When the potato was treated for four times,on the 7^th day after the last application,the final residue of Fluazinam in potato was below 0.008 mg/kg,and far lower than the MRL in Korea(0.05 mg/kg) or that in Japan and America(0.02 mg/kg).The results suggested that Fluazinam 50%SC be used in potapo at most four times at a dose of 25～33 mL/mu with a safe interval of 7 days from harvest.According to the results of this work and considering the MRL value of Fluazinam in pepper and potato in Korea,Japan and America,the MRL value of Fluazinam in our country were suggested that in pepper was 0.3 mg/kg and that in potato was 0.05 mg/kg respectively.