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Title
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Hydrophobicity-aided potentiometric detection of catecholamines, beta-agonists, and beta-blockers in a mixed-solvent capillary electrophoresis system
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Author
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Abstract
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| A series of cationic drug-like substances with distinct basicity, hydrogen-bonding ability, and hydrophobicity, including three catecholamines, two beta-agonists, and thirteen beta-blockers, was successfully detected in a capillary electrophoresis system using an end-capillary coupled potentiometric sensor consisting of a PVC-based liquid membrane deposited directly on a 100 m diameter copper rod. The electrophoretic separation was performed on a 72 cm×75 m id uncoated fused-silica capillary with an acidic background electrolyte containing phosphoric acid in a water-acetonitrile mixture, pH* 2.8. Samples were injected electrokinetically at 5.0 kV for 10 s and a running voltage of 19.5 kV was applied. Excluding the bufuralol/practolol pair, baseline separation of all substances was achieved in the developed CE system within 9 minutes. A linear relationship (R2 0.8752) between the sensitivity of the applied potentiometric detector and the parameter log P characterising the hydrophobicity of the analytes was demonstrated. The best observable limits of detection (LODs) were obtained for the highly hydrophobic substances, i. e. bufuralol (8.10×10-8 M injected concentration, S/N = 3), propranolol, alprenolol, and clenbuterol (ca. 1.10×10-7 M). In the case of hydrophilic catecholamines and carbuterol their LODs with potentiometric detection were lowered by a factor of almost one thousand, reaching a value of 6.6×10-5 M. |
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Language
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English
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Source (journal)
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Journal of separation science. - Weinheim, 2001, currens
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Publication
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Weinheim
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2009
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ISSN
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1615-9306
[print]
1615-9314
[online]
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DOI
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10.1002/JSSC.200800450
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Volume/pages
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32
:1
(2009)
, p. 135-146
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ISI
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000262738900018
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Full text (Publisher's DOI)
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