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Highly sensitive indirect photometric detection of cations by capillary electrophoresis with the cationic dye chrysoidine

journal contribution
posted on 2023-05-16, 14:26 authored by Johns, CA, Miroslav MackaMiroslav Macka, Paul HaddadPaul Haddad
The cationic dye, chrysoidine, has been used for the first time as a probe for the indirect photometric detection of cations. The dye has been used as a probe at concentrations of 5 mM, which is roughly an order of magnitude higher than for other cationic dyes used previously for the same purpose, in order to minimise electromigrational dispersion. Baseline instability was minimised by a combination of coating the capillary with poly(ethyleneimine), addition of a neutral polymer to the electrolyte, and the application of a small amount (20 mbar) of hydrodynamic pressure during the separation. Separation of a mixture containing alkali metals, alkaline earths, transition metals and lanthanides was achieved by the addition of 2-hydroxyisobutyric and lactic acid as complexing agents. Excellent peak shapes were observed over a wide range of analyte mobilities due to the moderate mobility of the probe. The high absorptivity (26 733 l mol−1 cm−1) provided by chrysoidine in comparison with typically used, less absorbing probes, was reflected in limits of detection which were typically less than 0.5 μM. These are amongst the lowest reported using hydrodynamic injection without the use of large volume stacking methods. The use of 2-hydroxyisobutyric and lactic acids as complexing agents at pH values close to their pKa values provided suitable buffering which was highlighted by very good reproducibility of migration time, corrected peak area and peak height.

History

Publication title

Journal of Chromatography A

Volume

997

Issue

1-2

Pagination

87-94

ISSN

0021-9673

Department/School

School of Natural Sciences

Publisher

Elsevier Science BV

Place of publication

Amsterdam, Netherlands

Rights statement

The definitive version is available at http://www.sciencedirect.com

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the chemical sciences

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