Step-gradient Capillary Electrochromatography

Euerby, Melvin R.; Gilligan, Declan; Johnson, Christopher M.; Bartle, Keith D.

doi:10.1039/a703175k

Cited by 35 publications

(12 citation statements)

References 8 publications

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“…O método mais simples de eluição por gradiente em CEC e mais fácil de ser adaptado aos instrumentos comerciais é chamado gradiente-por-etapa (step-gradient), utilizado pela primeira vez por Euerby et al 57 para separar uma mistura teste contendo diuréticos. Neste método, a separação é feita utilizando-se diferentes reservató-rios de entrada e saída, contendo a fase móvel em ordem crescente de força cromatográfica e o fluxo do eluente é interrompido a cada troca de fase móvel.…”

Section: 45 Modos De Operaçãounclassified

“…Neste método, a separação é feita utilizando-se diferentes reservató-rios de entrada e saída, contendo a fase móvel em ordem crescente de força cromatográfica e o fluxo do eluente é interrompido a cada troca de fase móvel. 57 Uma desvantagem deste método é o maior desgaste do capilar, ocasionado pela sua movimentação a cada troca de fase móvel, diminuindo seu tempo de vida.…”

Section: 45 Modos De Operaçãounclassified

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Eletrocromatografia capilar: contextualização, estado da arte e perspectivas

Segato¹,

Silva²,

Jardim³

2009

Quím. Nova

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ElEtrocromatografia capilar: contExtualização, Estado da artE E pErspEctivas milena pinotti segato, césar ricardo silva e isabel cristina sales fontes Jardim* Instituto de Química, Universidade Estadual de Campinas, CP 6154, 13084-971 Campinas -SP, BrasilRecebido em 25/3/08; aceito em 21/8/08; publiado na web em 26/1/09 CAPILLARY ELECTROCHROMATOGRAPHY: CONTEXTUALIZATION, STATE-OF-THE-ART AND PERSPECTIVES. Capillary electrochromatography (CEC) is a separation technique in which the mobile phase flow is based on the application of a voltage across a packed capillary, which generates an electroosmotic flow that transports the analytes along the capillary toward the detector. As it combines the separation mechanisms of high-performance liquid chromatography (HPLC) and of capillary electrophoresis (CE), CEC can be considered a hybrid of HPLC and CE. This review presents some fundamental aspects of CEC and is focused on the instrumental advances of the technique, such as column technology, operation modes and detection systems, presenting recent papers on these topics and some applications and perspectives about CEC.

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Section: 45 Modos De Operaçãounclassified

Eletrocromatografia capilar: contextualização, estado da arte e perspectivas

Segato¹,

Silva²,

Jardim³

2009

Quím. Nova

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“…A number of approaches to gradient CEC have been reported. Euerby et al [4] employed a step-gradient system in which solvent composition is changed in steps by simply changing the running buffer vial during the chromatographic rtm. Yan et al [5] used two high voltage supplies to control the electro-osmotic flow (EOF) of two different phases which are mixed before entering the CEC column; the true composition of the mobile phase at the column inlet is, however, unknown.…”

Section: Introductionmentioning

confidence: 99%

Simple interface for gradient elution CEC and coupled HPLC-CEC

1999

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SummaryAn interface which permits both gradient elntion capillary electrochromatography (CEC) and the coupling of high performance liquid chromatography (HPLC) to CEC is described. Mobile phase from an HPLC system with continuously variable composition is supplied on demand to the inlet of a CEC column, without the possibility of pressure driven flow. The interface also allows fractions separated by either reverse phase or normal phase HPLC to be transferred to a CEC column operated in reverse phase mode for further separation

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“…Among them, stepwise gradient elution of the mobile phase can be easily realized on commercial CE instruments. Therefore, it has been successfully applied to the analysis of pharmaceuticals [27], DNA additives [28], and aromatic compounds [29] and so forth. However, up till now the characteristics of EOF and the migration of solutes under stepwise gradient elution have not been clarified limiting its further application.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of electroosmotic flow and migration of neutral solutes under stepwise gradient elution of capillary electrochromatography

Zhang

Ping

et al. 2002

Electrophoresis

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A theoretical study on the velocity of electroosmotic flow (EOF) and the retention times of neutral solutes under multiple-step gradient of capillary electrochromatography (CEC) was carried out, focusing on that with three kinds of mobile phases. Through the model computations, the detaining time of the second kind of mobile phase in the column was proved to play an important role in affecting EOF. The variation speed of EOF was shown to be determined by the differences among dead times in different steps. In addition, the prediction of the retention times of 13 aromatic compounds under gradient mode was performed with the deduced equations. A relative error below 3.3% between the calculated and experimental values was obtained, which demonstrated the rationality of the theoretical deduction. Our study could not only improve the comprehension of stepwise gradient elution, but also be of significance for the further optimization of separation conditions in the analysis of complex samples.

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Step-gradient Capillary Electrochromatography

Cited by 35 publications

References 8 publications

Eletrocromatografia capilar: contextualização, estado da arte e perspectivas

Eletrocromatografia capilar: contextualização, estado da arte e perspectivas

Simple interface for gradient elution CEC and coupled HPLC-CEC

Characteristics of electroosmotic flow and migration of neutral solutes under stepwise gradient elution of capillary electrochromatography

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