Priego-Capote Feliciano, Luque de Castro Maria D
Department of Analytical Chemistry, Córdoba University, Córdoba, Spain.
Electrophoresis. 2005 Jun;26(12):2283-92. doi: 10.1002/elps.200500053.
An electrophoretic method for the simultaneous separation and determination of cationic and anionic surfactants based on double electrokinetic injection from the two ends of the capillary is proposed here. Nonaqueous capillary electrophoresis (NACE) with methanol as solvent was used to reduce the electroosmotic flow so that under these conditions the analytes migrate toward the corresponding electrode. The optimization step was the key to solve the problems associated with surfactants analysis (namely, adsorption on the capillary wall, micelle formation, and those issues related to the separation of homologous compounds). Good results were obtained with the proposed method both for the analysis of both spiked and natural samples, thus demonstrating the applicability of the proposed method for routine analysis. Finally, a comparison between the proposed method and two methods for independent analysis of cationic and anionic surfactants was made. The results showed that the precision (between 1.90 and 4.10% for repeatability and 7.43 and 8.98% for within-laboratory reproducibility, both expressed as relative standard deviation) and sensitivity (limits of detection and quantification between 0.52 and 1.88 microg/mL and between 1.73 and 6.20 microg/mL, respectively) are not affected by the CE mode. The resolution was similar to or better than that of the comparison methods and the analysis time was considerably shortened as both types of compounds were determined in a single run in only 9 min.
本文提出了一种基于从毛细管两端进行双电动进样同时分离和测定阳离子和阴离子表面活性剂的电泳方法。采用以甲醇为溶剂的非水毛细管电泳（NACE）来降低电渗流，使得在这些条件下分析物向相应电极迁移。优化步骤是解决与表面活性剂分析相关问题（即吸附在毛细管壁上、胶束形成以及与同系物分离相关的那些问题）的关键。所提出的方法在分析加标样品和天然样品时均取得了良好结果，从而证明了该方法用于常规分析的适用性。最后，将所提出的方法与两种分别独立分析阳离子和阴离子表面活性剂的方法进行了比较。结果表明，精密度（重复性的相对标准偏差为1.90%至4.10%，实验室内部重现性的相对标准偏差为7.43%至8.98%）和灵敏度（检测限和定量限分别在0.52至1.88μg/mL和1.73至6.20μg/mL之间）不受毛细管电泳模式的影响。分辨率与比较方法相似或更好，并且由于两种类型的化合物在仅9分钟的单次运行中即可测定，分析时间大大缩短。
