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Indirect spectrophotometric detection of inorganic anions in ion-exchange capillary electrochromatography


Boyce, M and Breadmore, MC and Macka, M and Doble, PA and Haddad, PR, Indirect spectrophotometric detection of inorganic anions in ion-exchange capillary electrochromatography, Electrophoresis, 21, (15) pp. 3073-3080. ISSN 0173-0835 (2000) [Refereed Article]

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DOI: doi:10.1002/1522-2683(20000901)21:15<3073::AID-ELPS3073>3.0.CO;2-H


The application of indirect spectrophotometric detection was investigated for a capillary electrochromatographic system in which an anion-exchange stationary phase (in the form of aminated latex particles) was coated onto the wall of a fused-silica capillary. The study has focused on the choice of the type and concentration of the absorbing coion (probe) added to the background electrolyte and the role of this species in manipulating the ion-exchange contributions to the separation with a view to controlling the selectivity of the separation. Common inorganic anions were used as analytes and nitrate, p-toluenesulfonate, nicotinate, and chromate were investigated as probes. It was found that most of these probes produced only a limited range of separation selectivities when their concentration was varied over the practically accessible range. p-Toluenesulfonate provided the greatest variation in selectivity, but peak distortion due to electromigration dispersion was evident for the faster ions. When variation of the separation selectivity - from predominantly electrophoretic in nature to predominantly ion-exchange in nature - was desired, this was best achieved by varying the type of probe rather than its concentration. For example, the nitrate probe provided predominantly electrophoretic separations with good peak shapes and high efficiencies. A comprehensive list of probes, ranked in order of ion-exchange selectivity coefficients determined by ion chromatography, was compiled and this proved to be a useful tool to assist in the selection of a probe for a desired separation selectivity. The limits of detection for the analytes and probes studied ranged from 20 - 55 {micro}mol for the chromate system to 230 - 600 {micro}mol for the nicotinate system, with nitrate and p-toluenesulfonate giving intermediate values.

Item Details

Item Type:Refereed Article
Research Division:Chemical Sciences
Research Group:Analytical chemistry
Research Field:Separation science
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the chemical sciences
UTAS Author:Boyce, M (Dr Mary Boyce)
UTAS Author:Breadmore, MC (Professor Michael Breadmore)
UTAS Author:Macka, M (Professor Mirek Macka)
UTAS Author:Doble, PA (Mr Philip Andrew Doble)
UTAS Author:Haddad, PR (Professor Paul Haddad)
ID Code:19458
Year Published:2000
Web of Science® Times Cited:29
Deposited By:Chemistry
Deposited On:2000-08-01
Last Modified:2010-02-20
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