嘧肽霉素在烟叶及土壤中的残留分析及消解动态

Residue and decline dynamics of cytosinpeptidemycin in tobacco and soil

研究建立了烟叶及土壤环境中嘧肽霉素残留的高效液相色谱(HPLC)检测方法:鲜烟叶样品采用V(乙腈)∶V(水)=19∶1的混合溶剂提取,干烟叶及土壤样品采用V(乙腈)∶V(水)=17∶3的混合溶剂提取,经PEP-SPE固相萃取柱净化,HPLC检测。结果表明:在0.05～2 mg/kg添加水平下,嘧肽霉素在鲜烟叶、干烟叶和土壤中的平均回收率分别为82.7%～89.6%、78.7%～81.5%和79.6%～97.8%,相对标准偏差(RSD)分别为4.9%～5.7%、2.1%～5.8%和3.2%～6.1%;烟叶和土壤中嘧肽霉素的最小检出量(LOD)均为0.05 mg/kg。采用所建立的方法测定了田间不同施药剂量、施药次数和采收时间下烟叶及土壤样品中嘧肽霉素的消解动态及最终残留。结果表明:嘧肽霉素在鲜烟叶和土壤中的半衰期分别为3.4～5.1 d和1.3～3.1 d;于烟草现蕾-成熟期,以2%嘧肽霉素水剂按有效成分28.2～42.3 g/hm2的剂量施药2～3次,距末次施药后7、14和21 d,烟叶及土壤中嘧肽霉素的残留量均低于LOD值(0.05 mg/kg)。

The field trial and sample analysis of cytosinpeptidemycin in tobacco leaf and soil were assessed.The sample of fresh tobacco leaf,cured tobacco leaf or soil was extracted with mixture of acetonitrile-water（19∶1 or 17∶3,V∶V） and filtrated with PEP-SPE,and then determined with the high performance liquid chromatography（HPLC） equipped an ultraviolet（UV） detector.The limit of detection（LOD） of this method was 0.05 mg/kg.The average additive recoveries fortified at 0.05-2 mg/kg levels were 82.7%-89.6% in fresh tobacco leaf,and 78.7%-81.5% in cured tobacco leaves,and 79.6%-97.8% in soil.The half-lives of cytosinpeptidemycin in tobacco leaf ranged 3.4-5.1 d,and 1.3-3.1 d in soil,respectively.The results showed that the ultimate residue of cytosinpeptidemycin in cured tobacco leaves and soil sampled in different interval were below LOD,when 2% cytosinpeptidemycin AS was applied with the label recommended dose.