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Preconcentration and frontal electroelution of amino acids for in-line solid-phase extraction–capillary electrophoresis

Breadmore, MC 2006 , 'Preconcentration and frontal electroelution of amino acids for in-line solid-phase extraction–capillary electrophoresis' , Analytica Chimica Acta, vol. 556, no. 1 , pp. 121-126 , doi:

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A new frontal electroelution approach that can be used for the preconcentration of amino acids in in-line solid-phase extraction–capillary electrophoresis (SPE–CE) has been developed. A single capillary was employed featuring a short monolithic SPE column created inside the capillary via photo-initiated, free-radical polymerisation of 3-sulfopropyl methacrylate and butyl methacrylate monomers. A weak electrolyte of dilute H2SO4, pH 2.9, was found to promote adsorption of the amino acids onto the SPE column. Elution of the amino acids was achieved using a dual solvation/ion-exchange transient boundary mobilised via EOF by using a strong electrolyte containing 62.5 mM ethylenediamine, pH 2.9 with H2SO4 and 40% (v/v) acetonitrile. Using these two electrolytes, tryptophan was adsorbed onto the SPE column in weak electrolyte and eluted via a frontal electroelution mechanism in the strong electrolyte. Injections up to 20 min, corresponding to over 14 column volumes (or 1400% of the capillary volume) of sample provided quantitative extraction of tryptophan from the weak electrolyte and were eluted without any loss in efficiency. This represents a practical increase of approximately 300-fold when compared to a typical hydrodynamic injection occupying 5% of the capillary volume.

Item Type: Article
Authors/Creators:Breadmore, MC
Keywords: Solid-phase extraction; Capillary electrophoresis; In-line SPE–CE; Frontal electroelution; Focusing
Journal or Publication Title: Analytica Chimica Acta
ISSN: 0003-2670
DOI / ID Number:
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