Potentiometric determination of coextraction constants of potassium salts in ion-selective electrodes utilizing a nitrobenzene liquid membrane phase

D S Silvester; E Grygolowicz-Pawlak; Eric Bakker

doi:10.1016/j.aca.2010.10.012

Back

Potentiometric determination of coextraction constants of potassium salts in ion-selective electrodes utilizing a nitrobenzene liquid membrane phase

Journal article

Open access

Peer reviewed

Potentiometric determination of coextraction constants of potassium salts in ion-selective electrodes utilizing a nitrobenzene liquid membrane phase

D S Silvester, E Grygolowicz-Pawlak and Eric Bakker

Analytica Chimica Acta, Vol.683(1), pp.92-95

2010

DOI: https://doi.org/10.1016/j.aca.2010.10.012

Files and links (2)

pdf

PDF - Author's Accepted Version (Open Access)478.92 kBDownload View

Accepted VersionPDF - Author Accepted Version (Open Access)CC BY-NC-ND V4.0, Open Access

url

https://doi.org/10.1016/j.aca.2010.10.012View

Published Version

Abstract

potentiometry

nitrobenzene

ITIES

phase boundary potential

coextraction constant

A theoretical treatment of potentiometric data is applied to calculate coextraction constants (K-1A) for three potassium salts from water into a liquid nitrobenzene phase. The experiment involves treating nitrobenzene as a membrane and contacting it with two aqueous solutions of different ion activities. In the presence of either a cation or anion exchanger, the ratio of activities of ions in the two aqueous phases gives rise to a potential difference across the membrane that depends upon the nature and charge of the counter ion of the ion-exchanger in excess. Here, the cation exchanger was chosen to be potassium tetrakis(4-chlorophenyl)borate (KTpClPB) and the anion exchanger was tetradodecylammonium chloride (TDDACI). TDDACI was incrementally added to the nitrobenzene phase containing a fixed concentration of KTpClPB, and the corresponding emf was recorded as a function of concentration of TDDACI. The membrane changes from one with cation exchanger properties (excess KTpClPB) to one with anion exchanger properties (excess TDDACI). The potential difference and shape of the titration curve can be predicted by theory based on the phase boundary potential model. Log(K-1A) values calculated for KCl, KNO3 and KClO4 in nitrobenzene were found as: -10.53 (+/- 0.09), -8.16 (+/- 0.05) and -5.63 (+/- 0.03) respectively, in accordance with the Hofmeister series of lipophilicity, and similar to those observed in PVC membranes containing other plasticizers. The method presented here offers the advantage over other methods to calculate K-1A, in that it is relatively experimentally simple without compromising the accuracy of the calculated coextraction constants. The ability to titrate directly into the liquid membrane phase affords a higher precision compared to the preparation of a series of PVC/plasticizer membranes with different compositions.

Details

Title: Potentiometric determination of coextraction constants of potassium salts in ion-selective electrodes utilizing a nitrobenzene liquid membrane phase
Authors: D S Silvester (Author) - Curtin University of Technology
E Grygolowicz-Pawlak (Author) - Curtin University of Technology
Eric Bakker (Author) - Curtin University of Technology
Publication details: Analytica Chimica Acta, Vol.683(1), pp.92-95
Publisher: Elsevier BV
Date published: 2010
DOI: 10.1016/j.aca.2010.10.012
ISSN: 0003-2670
Organisation Unit: University of the Sunshine Coast, Queensland
Language: English
Record Identifier: 99450024902621
Output Type: Journal article

Metrics

36 File views/ downloads

461 Record Views

4 Times Cited - Web of Science

InCites Highlights

These are selected metrics from InCites Benchmarking & Analytics tool, related to this output

Collaboration types: Domestic collaboration; International collaboration
Web Of Science research areas: Chemistry, Analytical