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Issue 5, 2004
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Quaternary ammonium substituted agarose as surface coating for capillary electrophoresis

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A novel positively charged polymer of quaternary ammonium substituted agarose (Q-agarose) has been synthesized and explored for use as a coating in capillary electrophoresis. The fast and simple coating procedure is based on a multi-site electrostatic interaction between the polycationic agarose polymer and the negatively charged fused-silica surface. By simply flushing fused-silica capillaries with hot polymer solution a positively charged, hydrophilic deactivation layer is achieved. The polymer surface provides an intermediate electroosmotic flow of reversed direction, over a range of pH 2–11, compared to unmodified fused-silica. The coating procedure was highly reproducible with an RSD of 4%, evaluated as the electroosmotic flow mobility for 30 capillaries prepared at 10 different occasions. The application of Q-agarose coated capillaries in separation science was investigated using a set of basic drugs and model proteins and peptides. Due to the intermediate electroosmotic flow generated, the resolution of basic drugs could be increased, compared to using bare fused-silica capillaries. Moreover, the coating enabled separation of proteins and peptides with efficiencies up to 300.000 plates m−1.

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Publication details

The article was received on 17 Dec 2003, accepted on 03 Mar 2004 and first published on 17 Mar 2004

Article type: Paper
DOI: 10.1039/B316492F
Analyst, 2004,129, 410-415

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    Quaternary ammonium substituted agarose as surface coating for capillary electrophoresis

    S. Ullsten, L. Söderberg, S. Folestad and K. E. Markides, Analyst, 2004, 129, 410
    DOI: 10.1039/B316492F

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