Ion-selective electrode for bismuth(III) in ethylenediamintetraacetate medium

Area of Science:

• Electrochemistry
• Analytical Chemistry
• Materials Science

Background:

• Ion-selective electrodes (ISEs) are crucial for determining metal ion concentrations.
• Developing sensitive and selective electrodes for bismuth(III) is important for various applications.
• Previous bismuth(III) electrodes faced limitations in sensitivity, selectivity, or operational stability.

Purpose of the Study:

• To construct and characterize a novel coated graphite-epoxy ion-selective electrode for bismuth(III) determination.
• To investigate the electrode's performance using different plasticizers and optimize its response.
• To evaluate the electrode's applicability in real-world sample analysis.

Main Methods:

• Fabrication of a graphite-epoxy based electrode incorporating a PVC membrane with a bismuth(III)-EDTA ion-pair and Aliquat 336S.
• Incorporation of dibutylphthalate (DBPh) or ortho-nitrophenyloctylether (o-NPOE) as plasticizers in the PVC membrane.
• Electrochemical characterization including potentiometric measurements, pH studies, and selectivity testing.

Main Results:

• The developed electrode exhibited a linear potentiometric response for bismuth(III) over a broad concentration range (1.0 x 10⁻⁸ to 1.0 x 10⁻¹ mol L⁻¹).
• Slopes of 56.8 and 59.2 mV/decade were achieved with DBPh and o-NPOE plasticizers, respectively.
• The electrode demonstrated excellent stability, with a lifetime exceeding one year and practical detection limits as low as 6.3 x 10⁻⁹ mol L⁻¹.

Conclusions:

• The novel coated graphite-epoxy ion-selective electrode provides a sensitive, selective, and stable platform for bismuth(III) quantification.
• The electrode's performance is influenced by the choice of plasticizer, with o-NPOE showing slightly better results.
• The electrode was successfully applied for bismuth(III) determination in an anti-acid sample, demonstrating its practical utility.