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Scientific article
English

Coulometric Calcium Pump for Thin Layer Sample Titrations

Contributors

Ghahraman Afshar, Majid; Crespo Paravano, Gaston Adrian; Bakker, Eric

Published in

Analytical chemistry, vol. 87, no. 19, p. 10125-10130

Publication date

2015

Abstract

A selective electrochemical calcium pump based on a fast diffusive calcium ionophore-based membrane is reported. An initially nonpolarized ionophore-based membrane allows one to establish a net calcium flux by applying a potential step function (i.e., 250 mV for 30 s). The resulting calcium flux is released into a microliter scale thin layer reservoir, and the resulting ion perturbation is monitored by either a potentiometric or a coulometric readout. This chemical perturbation in the thin layer thus acts as a titration agent that is precisely controlled by coulometry. A linear correlation between released and detected calcium is confirmed by the two different readout modes. Having demonstrated the efficiency of the calcium pump in background electrolyte solutions, a complexometric titration with known concentrations of EDTA in the thin layer sample was performed. With the potentiometric readout, titrations in the range of 0.25−0.75 mM gave a precision of 3%, whereas the coulometric readout gave a range of 0.02−0.12 mM and a precision of 2%. Improved precision is expected by better control of the thin layer geometry by microfabrication. The significance of this work is that the coupling of a selective calcium pump with a thin layer element can give rise to rapid and complete sample concentration changes and result in a promising platform for titrations either on the laboratory bench or for in situ measurements in environmental or diagnostic settings.

UNIGE affiliation entities

UNIGE research groups

Citation (ISO format)

GHAHRAMAN AFSHAR, Majid, CRESPO PARAVANO, Gaston Adrian, BAKKER, Eric. Coulometric Calcium Pump for Thin Layer Sample Titrations. In: Analytical chemistry, 2015, vol. 87, n° 19, p. 10125–10130. doi: 10.1021/acs.analchem.5b02856

Main files (1)

Article (Published version)

Identifiers

Journal ISSN

0003-2700
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Technical informations

Creation

09/10/2015 15:08:00

First validation

09/10/2015 15:08:00

Update

14/03/2023 23:41:35

Status update

14/03/2023 23:41:35

Last indexation

31/10/2024 01:30:25
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