Aranas Agnes T, Guidote Armando M, Quirino Joselito P
Department of Chemistry, Ateneo de Davao University, School of Arts and Sciences, Davao City, 8000, Philippines.
Anal Bioanal Chem. 2009 May;394(1):175-85. doi: 10.1007/s00216-009-2646-7. Epub 2009 Mar 3.
Sweeping is a powerful on-line sample preconcentration technique that improves the concentration sensitivity of capillary electrophoresis (CE). This approach is designed to focus the analyte into narrow bands within the capillary, thereby increasing the sample volume that can be injected, without any loss of CE efficiency. It utilizes the interactions between an additive [i.e., a pseudostationary phase (PS) or complexing agent] in the separation buffer and the sample in a matrix that is devoid of the additive used. The accumulation occurs due to chromatographic partitioning, complexation or any interaction between analytes and the additive through electrophoresis. The extent of the preconcentration is dependent on the strength of interaction involved. Both charged and neutral analytes can be preconcentrated. Remarkable improvements--up to several thousandfold--in detection sensitivity have been achieved. This suggests that sweeping is a superior and general approach to on-line sample preconcentration in CE. The focusing mechanism of sweeping under different experimental conditions and its combination with other on-line preconcentration techniques are discussed in this review. The recently introduced techniques of transient trapping (tr-trapping) and analyte focusing by micelle collapse (AFMC) as well as other novel approaches to on-line sample preconcentration are also described.
推扫是一种强大的在线样品预富集技术，可提高毛细管电泳（CE）的浓度灵敏度。该方法旨在将分析物聚焦到毛细管内的窄带中，从而增加可进样的样品体积，同时不会损失任何CE效率。它利用分离缓冲液中的添加剂[即假固定相（PS）或络合剂]与不含所用添加剂的基质中的样品之间的相互作用。富集是由于色谱分配、络合或分析物与添加剂之间通过电泳发生的任何相互作用而产生的。预富集的程度取决于所涉及相互作用的强度。带电和中性分析物均可进行预富集。检测灵敏度已实现显著提高——高达数千倍。这表明推扫是CE中在线样品预富集的一种优越且通用的方法。本文综述了不同实验条件下推扫的聚焦机制及其与其他在线预富集技术的结合。还介绍了最近引入的瞬态捕获（tr-捕获）和胶束塌陷分析物聚焦（AFMC）技术以及其他在线样品预富集的新方法。
