复配剂中霜脲氰在马铃薯和土壤中残留动态研究

Residue Dynamics of Cymoxanil in Mixed Formulation in Potatoes and Soil

采用田间试验方法,研究了霜脲氰在马铃薯及土壤中的残留动态,应用液相色谱法测定了霜脲氰在马铃薯和土壤中的残留量。结果表明,霜脲氰在马铃薯和土壤中消解较快,半衰期分别为2.26d和5.75d,施药3240gai·hm-23次时,末次施药距收获间隔28d,霜脲氰的残留量在马铃薯中低于0.0098mg·kg-1,在土壤中为ND～0.0100mg·kg-1。该药属易分解农药(T1/2<30d),按推荐使用剂量使用是安全的。

In order to make up a standard procedure for safe use of cymoxanil on potatoes, a field experiment was conducted to reveal the residue dynamics of cymoxanil in potatoes and soil. The residues of cymoxanil （the active ingredient of 1/9 in mixed formulation） in potatoes and soil were determined by liquid chromatography procedure with the delectation conditions of UV detector, wavelength 254 nm and mobile phase/water （1/1,V/V）. The method was accurate with the lowest detection limit, and could satisfy the requirement for rapid analysis of crymoxanil in samples. The average initial deposits （the active ingredient） in potatoes and soil at the application rate of 3 240 g ai.hm^-2 were 1.650 0 mg·kg^-1 and 0.110 0 mg·kg^-1 , respectively, and then residues in potatoes and soil decreased gradually as time went on. The dynamics of cymoxanil residues in potatoes and soil could be described, respectively, as y=l.0359e-0.3066t and y=0.0758e-0.1205t. The half-lives of cymoxanil in potatoes and soil were 2.26 days and 5.75 days, respectively. When sprayed 3 240 g ai ·hm^-2 on potatoes and soil two or three times, at the interval time of 3 days and 7 days, at the 28th day after the last application, the final residues of the cymoxanil were lower than 0.016 0 mg·kg^-1 in potatoes and ND-0.014 6 mg·kg^-1 in soil, and at the rate of 1 620 g ai·hm^-2, the final residue of Crymoxanil were ND and 0.009 2 mg·kg^-1 0.016 7 mg·kg^-1 , suggesting that cymoxanil belonged to non-persistent pesticides（T1/2〈30 days）.