Orejuela Eva, Silva Manuel
Department of Analytical Chemistry, Marie-Curie Building (Annex), Rabanales Campus, University of Cordoba, Cordoba, Spain.
Electrophoresis. 2005 Dec;26(23):4478-85. doi: 10.1002/elps.200500290.
A straightforward and sensitive method has been developed for the analysis of phosphorus-containing amino acid herbicides (glufosinate and aminomethylphosphonic acid, the major metabolite of glyphosate) in soil samples. For this purpose, the analytical features of two indocyanine fluorescent dyes, sulfoindocyanine succinimidyl ester (Cy5) and 1-ethyl-1-[5-(N-succinimidyl-oxycarbonyl)pentyl]-3,3,3,3-tetramethyl-indodicarbocyanine chloride, as labeling reagents for the determination of these herbicides by CZE with diode LIF detection were investigated. Practical aspects related to the labeling chemistry and CZE separation showed that the two probes behave similarly, Cy5 being the best choice for the determination of these herbicides on account of its higher sensitivity. The optimum procedure includes a derivatization step of the pesticides at 25 degrees C for 30 min and direct injection to CZE analysis, which is conducted within about 14 min using ACN in the running buffer. The lowest detectable analyte concentration ranged from 0.025 to 0.18 microg/L with a precision of 3.6-5.4%. These results indicate that indocyanine fluorescence dyes are useful as rapid and sensitive labels for the determination of these herbicides when compared with typical fluorescein dyes such as FITC and 5-(4,6-dichloro-s-triazin-2-ylamino) fluorescein, because they provide faster labeling reactions even at room temperature and the excess of reagent practically does not interfere the determination. Finally, the Cy5 method was successfully applied to soil samples without a preliminary clean-up procedure, and the herbicides were measured without any interference from coexisting substances. The recoveries of these compounds in these samples at fortification levels of 100-500 ng/g were 90-93%.
已开发出一种直接且灵敏的方法，用于分析土壤样品中的含磷氨基酸除草剂（草铵膦和草甘膦的主要代谢物氨甲基膦酸）。为此，研究了两种吲哚菁荧光染料，磺化吲哚菁琥珀酰亚胺酯（Cy5）和1-乙基-1-[5-(N-琥珀酰亚胺氧基羰基)戊基]-3,3,3,3-四甲基吲哚二碳菁氯化物，作为通过二极管激光诱导荧光检测的毛细管区带电泳法测定这些除草剂的标记试剂的分析特性。与标记化学和毛细管区带电泳分离相关的实际情况表明，这两种探针表现相似，由于Cy5具有更高的灵敏度，因此是测定这些除草剂的最佳选择。最佳程序包括在25℃下将农药衍生化30分钟，然后直接进样到毛细管区带电泳分析中，该分析在约14分钟内使用运行缓冲液中的乙腈进行。最低可检测分析物浓度范围为0.025至0.18μg/L，精密度为3.6 - 5.4%。这些结果表明，与典型的荧光素染料如异硫氰酸荧光素和5-(4,6-二氯-s-三嗪-2-基氨基)荧光素相比，吲哚菁荧光染料作为测定这些除草剂的快速且灵敏的标记物很有用，因为它们即使在室温下也能提供更快的标记反应，并且过量的试剂实际上不会干扰测定。最后，Cy5方法成功应用于未经预净化程序的土壤样品，并且在测定除草剂时没有受到共存物质的任何干扰。在这些样品中，当添加水平为100 - 500 ng/g时，这些化合物的回收率为90 - 93%。
