UNIGE document Scientific Article
previous document  unige:75926  next document
add to browser collection

Coulometric Calcium Pump for Thin Layer Sample Titrations

Published in Analytical Chemistry. 2015, vol. 87, no. 19, p. 10125-10130
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.
Full text
Research group Groupe Bakker
(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. https://archive-ouverte.unige.ch/unige:75926

146 hits

0 download


Deposited on : 2015-10-12

Export document
Format :
Citation style :