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Flow Chronopotentiometry with Ion-Selective Membranes for Cation, Anion, and Polyion Detection.
Journal article

Flow Chronopotentiometry with Ion-Selective Membranes for Cation, Anion, and Polyion Detection.

  • Ghahraman Afshar M Department of Inorganic and Analytical Chemistry, University of Geneva , Quai Ernest-Ansermet 30, CH-1211 Geneva, Switzerland.
  • Crespo GA Department of Inorganic and Analytical Chemistry, University of Geneva , Quai Ernest-Ansermet 30, CH-1211 Geneva, Switzerland.
  • Bakker E Department of Inorganic and Analytical Chemistry, University of Geneva , Quai Ernest-Ansermet 30, CH-1211 Geneva, Switzerland.
  • 2016-03-03
Published in:
  • Analytical chemistry. - 2016
Calcium
Chlorides
Electrochemical Techniques
Electrodes
Heparin
Humans
Hydroxides
Polymers
Protamines
Protons
English We report here on the development of a chronopotentiometric readout for ion-selective electrodes that allows one to record transition times in continuous flow conditions without the necessity to stop the flow. A sample plug of 150 μL is injected into the carrier solution (0.5 mM NaCl) and subsequently transported to the detection cell (∼20 μL) at moderate flow rates (∼0.5 mL min(-1)), where a short current pulse (5s) is applied between the ionophore-based working electrode and a biocompatible and nonpolarizable Donnan exclusion anion-exchanger membrane reference/counter electrode. Flow conditions bear an influence on the thickness of the aqueous diffusion layer and result in a shift of the chronopotentiometric transition time with respect to stopped flow. Two models based on rotating disk electrodes and flow chronopotentiometry at metal-based electrodes were used to corroborate the data. The method was successfully applied to the determination of calcium, chloride, alkalinity, acidity, and protamine with a range of ion-selective membranes. Because of the limiting exposure time of ca. 20 s of the membranes with the sample, this approach is demonstrated to be useful for the detection of protamine in the therapeutic range of undiluted human blood.
Language
  • English
Open access status
closed
Identifiers
Persistent URL
https://sonar.rero.ch/global/documents/252296
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