超高效液相色谱-串联质谱分析烟嘧磺隆在玉米和土壤中的残留消解动态

[目的]采用超高效液相色谱-质谱联用测定烟嘧磺隆在土壤、玉米植株和玉米籽粒中的消解动态和最终残留。[方法]土壤、玉米植株和玉米籽粒样品经0.2 mol/L磷酸钾缓冲液(pH 7.8)-甲醇提取,提取液用磷酸酸化至pH 2.5后经C18固相萃取柱净化,在ESI+MRM模式下进行检测。[结果]当烟嘧磺隆添加浓度水平为0.001～0.200 mg/kg时,其在玉米植株、玉米籽粒和土壤中的平均回收率为88.6%～99.2%,相对标准偏差(RSD)为1.2%～6.9%;在土壤、玉米籽粒中的检出限为0.001 mg/kg,在玉米植株中的检出限为0.002mg/kg。烟嘧磺隆在土壤中的半衰期为8.6～19.6 d,在玉米植株中的半衰期为0.6～5.5 d;按推荐剂量施药,在青玉米期及成熟期玉米籽粒中烟嘧磺隆的最终残留量均低于定量限。[结论]为烟嘧磺隆的田间合理使用提供了借鉴。

Dissipation Dynamics of Nicosulfuron in Corn and Soil by UPLC-MS/MS

[Objective] The aim was to determine dynamic of nicosulfuron and final residue in soil,corn plant and corn by using ultra performance liquid chromatography coupled with electrospray tandem mass spectrometry(UPLC-ESI-MS/MS).[Method] Soil,corn plant and corn samples were extracted with 0.2 mol/L potassium phosphate(pH 7.8) solution/methanol,and the extract was adjusted to pH =2.5,and purified by solid phase extraction(SPE) on waters C18 cartridges,and then quantified by mass spectometry in positive ion mode using multiple-reaction mornitoring(MRM).[Result] When the samples were spiked with nicosulfuron at 0.001-0.200 mg/kg levels,the overall average recoveries for nicosulfuron ranged from 88.6% to 99.2% and the RSDs was 1.2%-6.9%.The LODs was 0.001 mg/kg in corn and soil,and 0.002 mg/kg in corn plant.The half-life of nicosulfuron ranged from 0.6 to 5.5 days in corn plant,and ranged from 8.6 to 19.6 days in soil.If corn was sprayed at the recommended dosages,the final residues of nicosulforn in green or harvested corn were far lower than LODs.[Conclusion] The result provides reference for the rational use of nicosulfuron in field.