On-Line Sample Preconcentration and Separation Technique Based on Transient Trapping in Microchip Micellar Electrokinetic Chromatography

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• 作者：Kenji Sueyoshi ; Fumihiko Kitagawa ; Koji Otsuka
• 刊名：Analytical Chemistry
• 出版年：2008
• 出版时间：February 15, 2008
• 年：2008
• 卷：80
• 期：4
• 页码：1255 - 1262
• 全文大小：390K
• 年卷期：v.80,no.4(February 15, 2008)
• ISSN：1520-6882

文摘

This paper describes a novel on-line sample preconcentration and separation technique named transient trapping(tr-trapping), which improves the efficiencies of separationand concentration by using a partially injected shortmicellar plug in microchip electrophoresis. Although alonger separation length often provides a better resolutionof complexed or closely migrating analytes, our proposedtheoretical model indicated that a trap-and-release mechanism enables a short micellar zone, which was partiallyinjected into the separation channel, to work as aneffective concentration and separation field. Applicationof the tr-trapping technique to microchip micellar electrokinetic chromatography (MCMEKC) was performed ona newly fabricated 5-way-cross microchip by using sodiumdodecyl sulfate and rhodamine dyes as test micelle andanalytes, respectively. When the injection times of micelle(t_inj,M) and sample solution (t_inj,S) were 1.0 and 2.0 s,respectively, both the preconcentration and separation ofthe dyes were completely finished within only 3.0 s. Att_inj,S of 8.0 s, a 393-fold improvement of the detectabilitywas achieved in comparison with conventional MCMEKC.The resolution obtained with tr-trapping-MCMEKC wasalso better than that with conventional MCMEKC in spiteof the 160-fold shorter length of the injected micellar zoneat t_inj,M of 1.0 s. These results clearly demonstrated thatthe tr-trapping technique in MCMEKC provides a rapid,high-resolution and detectability analysis even in the shortseparation channel on the microchips.