Goodwin Lee, Startin James R, Keely Brendan J, Goodall David M
Chemistry Department, University of York, Heslington, York YO10 5DD, UK.
J Chromatogr A. 2003 Jul 4;1004(1-2):107-19. doi: 10.1016/s0021-9673(03)00572-7.
The potential of capillary electrophoresis combined with mass spectrometry for the simultaneous determination of two herbicides (glyphosate and glufosinate) and their metabolites (aminomethylphosphonic acid and methylphosphinicopropionic acid) as the native species is demonstrated utilising a simple microelectrospray interface. The interface uses the voltage applied to the CE capillary to drive separation and generate the electrospray, avoiding sample dilution associated with the use of a sheath liquid interface. The chemistry of the internal walls of the capillary has a marked influence on peak shape, and appropriate choice is essential to successful operation of the interface. A linear polyacrylamide coated capillary, which has no electroosmotic flow, gave best reproducibility, with precision of migration time and peak area in the range 1-2 and 7-12% RSD, respectively, for the four analytes. Limits of detection, low-pg on-column, are substantially better than for previous methods and calibration curves over the range 1-100 microM have R2 values greater than 0.97. The observed concentration limit of detection for glyphosate in water is 1 microM and for a water-acetone extract of wheat is 2.5 microM, allowing the underivatised herbicide to be detected at 10% of the maximum residue limit in wheat.
利用简单的微电喷雾接口，证明了毛细管电泳与质谱联用同时测定两种除草剂（草甘膦和草铵膦）及其代谢物（氨甲基膦酸和甲基膦酰基丙酸）的潜力。该接口利用施加在毛细管电泳毛细管上的电压驱动分离并产生电喷雾，避免了与使用鞘液接口相关的样品稀释。毛细管内壁的化学性质对峰形有显著影响，正确选择对于接口的成功运行至关重要。一种无电渗流的线性聚丙烯酰胺涂层毛细管具有最佳的重现性，四种分析物的迁移时间和峰面积精密度分别在1-2%和7-12%相对标准偏差范围内。柱上低皮克级的检测限比以前的方法有显著提高，1-100微摩尔范围内的校准曲线的R2值大于0.97。在水中草甘膦的观测浓度检测限为1微摩尔，在小麦的水-丙酮提取物中为2.5微摩尔，使得未衍生化的除草剂能够在小麦最大残留限量的10%水平被检测到。
