甲磺隆除草剂的测定方法及其吸附行为研究

采用批量平衡法系统研究了甲磺隆除草剂在几种土壤（熟化红壤、砖红壤性红壤、红筋泥、砖红壤）和矿物（高岭石、针铁矿、和Ca²⁺、Al³⁺、Cu²⁺单离子饱和蒙脱石）上的吸附行为.建立了硼酸-硼砂缓冲液体系的毛细管电泳测定甲磺隆的分析方法.甲磺隆在本实验条件下能够与土壤中的杂质达到基线分离,迁移时间为4.6 min.对比实验表明,毛细管电泳法测定甲磺隆与高效液相色谱法具有一致性.然而,毛细管电泳法能显著节省测试时间和成本,在本类吸附实验研究中具有很好的应用价值.吸附实验数据分析表明甲磺隆的吸附行为都可以用Freundlich模型描述,矿物和土壤的K_f值分别在0.82～199.69和1.97～10.48范围.在几种影响甲磺隆吸附的因素中,pH的影响作用最为显著,说明静电作用可能是甲磺隆在土壤及矿物上吸附的主要机理.

Study on the Determination of Metsulfuron-Methyl and Its Adsorption Behavior on Typical Soils and Minerals

Adsorption behavior of metsulfuron-methyl on soils and minerals was investigated using batch experiment. The concentration of metsulfuron-methyl in supernatant was analyzed by capillary electrophoresis (CE) method. Metsulfuron-methyl, whose peak centered at 4.6 min in capillary electrophoresis chromatogram, was well separated from impurities in soil slurry. CE was shown to be fast with low operating cost in the routine determination of the herbicide, which was further confirmed by high performance liquid chromatograph (HPLC). Sorption isotherms were fitted to the Freundlich equation, where the parameter Kf was in the range of 0.82~199.69 for minerals and 1.97~10.48 for soils, respectively. Among the various factors influencing the sorption behavior of metsulfuron-methyl, soil pH appears to be the most important one. The electrostatic interaction mechanism was applied in the explanation of the sorption behavior of metsulfuron-methyl in this work.