草甘膦的邻硝基苯磺酰氯柱前衍生高效液相色谱分析

Determination of Glyphosate by High Performance Liquid Chromatography with ο-Nitrobenzenesulfonyl Chloride as Derivatization Reagent

以邻硝基苯磺酰氯（NBSC）为衍生化试剂，建立了柱前衍生草甘膦的反相高效液相色谱紫外检测法，并对衍生化条件进行了优化。最佳衍生化条件为：衍生温度25℃，反应时间10min，硼砂缓冲溶液浓度0．25mol／L（pH9．0），草甘膦与NBSC的摩尔比为1：5。HPLC分析条件为：采用Lichrospher C18柱，流速1．0mL／min，柱温30℃，检测波长230nm，流动相为体积比20：80的甲醇-0．05mol／L磷酸盐缓冲溶液（pH5．5）。实验结果表明，草甘膦的质量浓度在0．05～1．0g／L范围内线性关系良好，相关系数（r^2）为0．9993，检出限为6．25mg／L。该方法反应条件温和，操作简单，衍生产物稳定。

A derivatization method for the determination of glyphosate was developed by using o-nitrohenzenesulfonyl chloride as derivatization reagent. The optimized conditions of derivatization were as follows： reaction temperature： 25 ℃, reaction time： 10 min, buffer solution： 0.25 mol/L borate buffer（pH 9.0） , the molar ratio of glyphosate to o-nitrobenzenesulfonyl ： 1 ： 5. The optimal chromatographic conditions were as follows： Lichrospher C18 column（5 μm, 4.6 mm× 250 mm） , detection wavelength： 230 nm, flow rate： 1.0 mL/min, mobile phase： methanol - pH 5.5 0.05 mol · L^-1 phosphate buffer（20 ： 80）. Under the optimal conditions, the calibration curve for glyphosate was linear in the range of 0. 05 - 1.0 g · L^-1 with a correlation coefficient （ r2 ） of 0. 999 3. The limit of detection was 6.25 mg· L^-1 . The method was simple, rapid and reliable, and was suitable for the determination of glyphosate in general laboratory.