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Chronopotentiometric Carbonate Detection with All-Solid-State Ionophore-Based Electrodes

Published in Analytical Chemistry. 2014, vol. 86, no. 13, p. 6307-6314
Abstract We present here for the first time an all-solid-state chronopotentiometric ion sensing system based on selective ionophores, specifically for the carbonate anion. A chronopotentiometric readout is attractive because it may allow one to obtain complementary information on the sample speciation compared to zero-current potentiometry and detect the sum of labile carbonate species instead of only ion activity. Ferrocene covalently attached to the PVC polymeric chain acts as an ion-to-electron transducer and provides the driving force to initiate the sensing process at the membrane–sample interface. The incorporation of a selective ionophore for carbonate allows one to determine this anion in a background electrolyte. Various inner electrolyte and all-solid-state-membrane configurations are explored, and localized carbonate depletion is only observed for systems that do not contain ion-exchanger additives. The square root of the transition times extracted from the inflection point of the chronopotentiograms as a function of carbonate specie concentration follows a linear relationship. The observed linear range is 0.03–0.35 mM in a pH range of 9.50–10.05. By applying the Sand equation, the diffusion coefficient of carbonate is calculated as (9.03 ± 0.91) 10–6 cm2 s–1, which corresponds to the established value. The reproducibility of assessed carbonate is better than 1%. Additionally, carbonate is monitored during titrimetric analysis as a precursor to an in situ environmental determination. Based on these results, Fc-PVC membranes doped with ionophores may form the basis of a new family of passive/active all-solid-state ion selective electrodes interrogated by a current pulse.
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JAROLIMOVA, Zdenka et al. Chronopotentiometric Carbonate Detection with All-Solid-State Ionophore-Based Electrodes. In: Analytical Chemistry, 2014, vol. 86, n° 13, p. 6307-6314. doi: 10.1021/ac5004163 https://archive-ouverte.unige.ch/unige:40159

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Deposited on : 2014-09-10

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