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  • Determination of the leaching of polymeric ion-selective membrane components by stripping voltammetry.

Determination of the leaching of polymeric ion-selective membrane components by stripping voltammetry.

Talanta (2010-03-20)
Beata Paczosa-Bator, Robert Piech, Andrzej Lewenstam
ABSTRACT

This paper focuses on the quantitative determination of the loss of the components from plastic membranes of ion-selective electrodes (ISEs) during contact with aqueous bathing solutions. The leaching processes, which affect the ISE responses, are rarely characterized by independent methods. For this purpose, differential pulse cathodic stripping voltammetry (DP CSV) is used. This method, owing to its high sensitivity, acceptable recovery and accuracy, is a good tool to characterize the kinetics of leakage of the lipophilic salts. Sodium tetraphenylborate (NaTPB) leakage from the PVC-based sodium-selective membrane containing two different plasticizers, o-nitrophenyl octyl ether (o-NPOE) or di(2-ethylhexyl) sebacate (DOS) is presented. Correlation between the rate of leaching of the lipophilic salt and dielectric constants of the plasticizers is observed. The data obtained by DP CSV correlate well with potentiometric and electrochemical impedance responses. The observed outflow of TPB(-) is associated with decreasing potentiometric sensitivity to sodium and increasing bulk membrane resistance.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Ammonium tetraphenylborate, 99%
Pricing and availability is not currently available.
Sigma-Aldrich
Potassium tetraphenylborate, 97%
Pricing and availability is not currently available.
Sigma-Aldrich
Sodium tetraphenylborate, puriss. p.a., ACS reagent, ≥99.5% (NT)
Pricing and availability is not currently available.
Sigma-Aldrich
Sodium tetraphenylborate, ACS reagent, ≥99.5%
Pricing and availability is not currently available.