不同剂型吡虫啉在烟叶和土壤中的残留及消解动态

Residue and dissipation for different formulations of imidacloprid in tobacco leaf and soil

采用高效液相色谱检测技术，于2010—2011年开展了吡虫啉可溶液剂、可湿性粉剂、微乳剂和颗粒剂4种常见剂型的不同施药剂量、不同施药次数和采收间隔期的田间试验，研究了不同剂型吡虫啉在烟叶和土壤中的残留降解规律与最终残留量。结果表明，在3个添加水平（0.01～5 mg/kg）、5次重复下，鲜烟叶、干烟叶和土壤中吡虫啉的平均回收率和相对标准偏差（RSD）分别为85.6% ～89.3%，5.0% ～5.7%；85.0% ～88.3%，3.5% ～5.0%；84.1% ～91.5%，3.4% ～8.0%；符合农药残留检测要求。吡虫啉最小检出量（LOD）为0.3 ng（S/N=3），最低检测浓度（LOQ）分别为：鲜烟叶0.01 mg/kg，干烟叶0.03 mg/kg，土壤0.01 mg/kg。由于推荐剂量不同，不同剂型农药在烟叶上的原始沉积量有较大差别，可溶液剂、可湿性粉剂、微乳剂和颗粒剂4种剂型的吡虫啉降解速率均较快，半衰期分别为5.7～6.6、3.1～3.7、5.0～5.1和10.5～11.4 d。在不同处理的干烟叶中，吡虫啉残留量有明显差异，根据国际烟草科学合作研究中心（CORESTA）的指导性残留限量为5 mg/kg，建议大田喷雾施药的3种剂型（可溶液剂、可湿性粉剂和微乳剂）安全间隔期为14 d，移栽期穴施的颗粒剂安全间隔期为70 d。

The field trial on tobacco leaf and soil on four formulations of imidacloprid,including soluble concentrate （SL）,wettable powder （WP）,micro-emulsion （ME） and granule （GR） were performed through orthogonality experiment considering different dosages,different application times and recovery intervals in year 2010-2011.The samples were analyzed by high-performance liquid chromatography （HPLC）.Imidacloprid residue dissipation and final residues of different formulations of imidacloprid in tobacco leaf and soil were studied.The average recoveries at 3 different levels and 5 replicates were from 85.6% to 89.3%,85.0% to 88.3% and 84.1% to 91.5%,with relative standard deviations （RSDs） from 5.0% to 5.7%,3.5% to 5.0%,and 3.4% to 8.0% in fresh tobacco leaf,cured tobacco leaf and soil,respectively.The limit of detection （LOD） was 0.3 ng（S/N=3）,and the limit of quantification（LOQ） was 0.01,0.01 and 0.03 mg/kg in fresh tobacco leaf,soil and cured tobacco leaf.The dissipation rates of four kinds formulation of imidacloprid were fast with half-lives of 5.7-6.6,3.1-3.7,5.0-5.1,10.5-11.4 d,respectively.The pesticide residues at different dosages,different frequencies and intervals in cured tobacco leaves varied in these situations.According to the GRL of CORESTA,14 days harvest intervals were recommended for three formulations sprayed at the growth phase and 70 days for granules which used into soil when transplanting.