二氯喹啉酸在水稻、土壤和田水中消解动态及残留

为评价二氯喹啉酸在水稻及其土壤中的安全性,建立其在水稻上的使用规范,于2008、2009年在杭州、济南和铁力三地进行田间试验,研究了二氯喹啉酸在水稻、土壤和田水中消解动态及最终残留量。建立了二氯喹啉酸在水稻、土壤和田水中残留量的超高效液相色谱串联质谱测定方法。在添加水平5～100μg.kg-1范围内,二氯喹啉酸的平均回收率在81.6%～105.7%之间,相对标准偏差均低于17.9%。残留试验结果表明,二氯喹啉酸在植株、土壤和田水中消解均符合一级动力学方程,消解半衰期分别为16.4～18.6、16.6～21.9和15.4～16.9 d;二氯喹啉酸在植株、土壤、糙米和稻壳中最终残留量均未检出（〈5μg.kg-1）。若二氯喹啉酸在水稻中的最高残留限量推荐值为0.5 mg.kg-1,建议每年以有效成分25 g.mu-1的剂量,于水稻移栽后10 d喷施1次,用于防治水稻田中稗草。

Residues and degradation dynamics of quinclorac in paddy plant,soil and paddy water

Field residues and degradation dynamics of quinclorac in paddy field were carried out in Hangzhou,Jinan and Tieli.UPLC-ESI/MS methods for determination of quinclorac residues in paddy plant,soil and water were developed.The average recoveries of quinclorac at fortified level 5～100 μg·kg-1 were 81.6%～105.7%,with RSDs of less than 17.9%.The degradation of quinclorac in paddy plant,soil and paddy water followed the first-order kinetics.The half lives of quinclorac were in the range from 16.4 to 18.6 days in paddy plant,from 16.6 to 21.9 days in soil and from 15.4 to 16.9 days in paddy water respectively.Non-detectable residue was found in paddy plant,soil,rice and rice hull finally.25 g a.i.·mu-1 spray after 10 days transplanting was proposed if 0.5 mg·kg-1 was considered as the maximum residue limit of quinclorac.