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Use of potentiometric detection in (ultra) high performance liquid chromatography and modelling with adsorption/desorption binding kinetics

Journal Contribution - Journal Article

Observation of a potentiometric sensor's response behaviour after injection in flow injection analysis at different concentrations allowed studying "on" and "off" kinetics of the analyte's adsorption/diffusion behaviour. The alkaloid metergoline was mostly used as an example. k(on) and k(off) rate constant values were measured, and the association constant K-ass, and Delta G values of the analyte-surface interaction were calculated with an adsorption-based model which proved to be fully applicable. k(on) increased by decreasing the sensor dimensions, while k(off) was unaffected by miniaturization. Increasing acetonitrile concentrations in the running buffer increased k(off), while k(on) was unaffected. The experimentally determined Delta G values of the analyte-surface interaction showed a linear relation to the response of the sensor, in my. This knowledge was applied to optimize the potentiometric detection of plant alkaloids in (U)HPLC. Sub-micromolar detection limits were obtained with the potentiometric detector/(U)HPLC combination. This is the first time that the response rates and the response itself can be modelled accurately for coated wire potentiometric sensors, and it is the first application of a potentiometric detector in UPLC. (C) 2013 Elsevier B.V. All rights reserved.
Journal: Analytica chimica acta
ISSN: 0003-2670
Volume: 777
Pages: 25 - 31
Publication year:2013
Keywords:A1 Journal article
BOF-keylabel:yes
BOF-publication weight:6
CSS-citation score:1
Authors from:Higher Education
Accessibility:Closed