噻菌茂在烟叶和土壤中的残留消解动态及安全性评价

为明确噻菌茂在烟草上使用后的环境安全性,建立了烟叶和土壤中噻菌茂残留的检测方法,并在山东和湖南两地开展了为期两年的噻菌茂在烟叶及其土壤中的消解动态和最终残留研究。结果表明,采用甲醇/水（70：30,V：V）提取,石油醚、二氯甲烷萃取,弗罗里硅土净化,高效液相色谱（HPLC-UV）测定,在0.01～5.0mg.kg-1添加水平下,噻菌茂在鲜烟叶、干烟叶和土壤中的平均回收率分别为90.50%～93.84%、88.19%～91.90%和88.34%～93.04%,相对标准偏差（RSD）分别为1.72%～2.79%、1.83%～4.13%、2.00%～2.71%。噻菌茂的最小检出量为1.4×10-12g,最低检出浓度分别为：鲜烟叶0.01mg.L-1,干烟叶0.01mg.L-1,土壤0.005mg.L-1。田间试验结果表明,噻菌茂在烟叶和土壤中消解较快,半衰期分别为2.85～3.44d和2.77～3.26d。噻菌茂可湿性粉剂按有效成分250g.hm-2（推荐高剂量）和375g.hm-（21.5倍推荐高剂量）于烟草旺长期-成熟期兑水施药3～4次,烟叶中噻菌茂最终残留量随采收间隔时间的延长而呈递减趋势,距末次施药后间隔7d采收的烟叶中噻菌茂的残留量为1.102～4.230mg.kg-1,21d残留量降为0.082～1.813mg.kg-1;而土壤中噻菌茂最终残留量均未检出（≤0.005mg.kg-1）。

Residue Dynamics and Safety Evaluation of Saijunmao in Tobacco Leaves and Soil

To assess the environmental safety of applications of fungicide saijunmao in tobacco,the analytical method and residue dynamics as well as final residues in tobacco and soil were investigated.Tobacco-leaf and soil samples were extracted with methanol/water（70：0,V：V）.The extract was partitioned with petroleum ether and dichloromethane successively,and cleaned up on a florisil column with an dichloromethane-methanol mixture（1：1）before its determination by high performance liquid chromatography（HPLC）equipped with an ultraviole（tUV）detector.The average recoveries at spiked levels of 0.01～5.0 mg.kg-1 ranged from 90.50%～93.84% for green tobacco leaf,88.19%～91.90% for dried tobacco leaf and 88.34%～93.04% for soil,with relative standard deviations（RSD）of 1.72%～2.79%,1.83%～ 4.13% and 2.00%～2.71%,respectively.The limit of detection（LOD）was 1.4×10-12 g,while the limit of quantification（LOQ）were determined as 0.01 mg.L-1 for green tobacco leaf,0.01 mg.L-1 for dried tobacco leaf and 0.005 mg.L-1 for soil,respectively.Results of saijunmao degradation dynamics showed that half-life values（T1/2）were 2.85～3.44 d in green tobacco leaves and 2.77～3.26 d in soil,respectively.The final residues of saijunmao in dried tobacco leaves and soil were determined after the third and fourth application at levels of 250 g.a.i..hm-2 and 375 g.a.i..hm-2.The final residues were 1.102～4.230 mg.kg-1 7 days and 0.082～1.813 mg.kg-1 21 days after the last application in dried tobacco leaves.Meanwhile,the residues in soil were not detected.