Determination of Dysprosium(III) Ion in Soil and Sediment Samples by an Original Potentiometric Dysprosium(III) Membrane Sensor

Abstract

A PVC membrane electrode for dysprosium(III) [Dy(III)] ions was constructed, having its basis on benzoxazoleguanidine (BG) as a suitable ionophore. The sensor presents a linear dynamic range of 1.0 × 10⁻⁶–1.0 × 10⁻¹ M, with a Nernstian slope of 19.5 ± 0.4 mV decade⁻¹ and a detection limit of 4.7 × 10⁻⁷ M. The response time is quick (less than 10 s). It can be used in the pH range of 3.3–8.4, and its duration is at least 2 mo without any considerable, noticeable potential divergence. The recommended sensor revealed comparatively good selectivity with respect to most alkali, alkaline earth, some transition, and heavy metal ions. It was successfully employed as an indicator electrode in the potentiometric titration of Dy(III) ions with EDTA. The membrane sensor also applied to the determination of concentration of Dy(III) ions in soil and sediment samples. Validation with certified reference materials (CRMs) was also carried out.

Keywords:

• Dysprosium sensor
• PVC membrane
• potentiometry
• benzoxazoleguanidine
• ion-selective electrode

The authors are greatly indebted to the Quchan University Research Council for financially supporting this research.