Hou Li, Lee Hian Kee
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Republic of Singapore 117543.
Anal Chem. 2003 Jun 1;75(11):2784-9. doi: 10.1021/ac020753z.
Dynamic three-phase (liquid-liquid-liquid) microextraction was developed for capillary electrophoresis. Four aromatic amines as model compounds were extracted from 4-mL aqueous samples adjusted to basic condition (donor solution) through a small volume of organic solvent impregnated in a hollow fiber, which was held by the needle of a conventional syringe, and retracted into a 5-microL acidic acceptor solution inside the syringe. A renewable organic film and aqueous sample plug were formed inside the hollow fiber with the repeated movement of the syringe plunger enabled by a programmable syringe pump. This is believed to be the first reported instance of a semiautomated dynamic liquid-liquid-liquid microextraction (LLLME) procedure. Following this microextraction, the 5-microL acceptor solution was analyzed by capillary zone electrophoresis (CE). This new technique provided approximately 140-fold enrichment in 20 min. Utilizing 4-chloroaniline as internal standard, dynamic LLLME could provide good reproducibility (<4.0%). In addition, this method allowed the direct transfer of extracted analytes to a CE system for analysis.
开发了用于毛细管电泳的动态三相（液-液-液）微萃取方法。以四种芳香胺作为模型化合物，通过浸渍在中空纤维中的少量有机溶剂，从4 mL调至碱性条件的水样（供体溶液）中进行萃取，该中空纤维由传统注射器的针头固定，并回缩至注射器内5 μL的酸性受体溶液中。通过可编程注射泵使注射器柱塞重复运动，在中空纤维内部形成可再生有机膜和水样塞。据信这是首次报道的半自动动态液-液-液微萃取（LLLME）方法实例。该微萃取之后，对5 μL受体溶液进行毛细管区带电泳（CE）分析。这项新技术在20分钟内实现了约140倍的富集。以4-氯苯胺作为内标，动态LLLME可提供良好的重现性（<4.0%）。此外，该方法可将萃取的分析物直接转移至CE系统进行分析。
