烟嘧磺隆在玉米和土壤中的残留及消解动态研究

通过液相色谱-质谱联用仪定量定性分析,研究了75%烟嘧磺隆水分散粒剂在玉米籽粒、玉米植株和土壤中的残留及消解动态。结果表明,烟嘧磺隆在玉米植株中的空白添加平均回收率为78.32%～86.02%,相对标准偏差为2.28%～5.98%;在籽粒中的空白添加平均回收率为82.95%～88.37%,相对标准偏差为2.22%～5.21%;在土壤中的空白添加平均回收率为92.96%～98.84%,相对标准偏差为1.73%～2.91%。其最小检出量为0.005ng,在玉米植株、籽粒及土壤中的最低检测限量为0.002 5mg/kg。2009、2010年在河南省和黑龙江省两地的田间残留试验结果表明:烟嘧磺隆在玉米植株中的消解半衰期为0.58～1.45d,在土壤中的消解半衰期为9.63～13.59d;烟嘧磺隆在玉米籽粒、玉米植株及土壤中的最终残留量均为未检出,说明该药为低残留、易消解农药。建议将75%烟嘧磺隆水分散粒剂用于防治玉米田杂草时,施药的有效成分不得高于90g/hm2,于玉米苗后三至五叶期施药1次。

Residues and Dissipation Dynamics of Nicosulfuron in Corn and Soil

Dissipation dynamics and residues of 75% nicosulfuron WDG in corn,corn plant and soil were studied under field conditions.The nicosulfuron was determined by UPLC-MS.The fortified recoveries in corn,corn plant and soil at 0.05-0.2 mg/kg were 78.32%-98.84%,with the relative standard deviation of 1.73%-5.98%.The detection limit of the analytical method was 0.005 ng at a signal-to-noise ratio of 3,and the limit of quantification was 0.002 5 mg/kg in corn,corn plant and soil.The dissipation dynamics of nicosulfuron in the field trials in Henan and Heilongjiang province were investigated in 2009 and 2010.The results showed that the half-life period of nicosulfuron was 0.58-1.45 d in corn plants,and 9.63-13.59 d in soil.The final residues of nicosulfuron in corn,corn plant and soil were all not detected.No residue detected and short half-life in corn,corn plant and soil suggested that nicosulfuron was an easily dissipated and low residue pesticide,so it could be safely used on corn crops when the dosage below 90 g.a.i./ha.