Determination of Ytterbium(III) Ions in Soil and Sediment Samples by a New Polymeric Yb³⁺-PVC Membrane Sensor

Abstract

A polyvinyl chloride (PVC) membrane sensor for ytterbium(III) ions was prepared, based on 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene (BBT) as a membrane carrier. The sensor illustrates the following characteristics: a linear dynamic range of 1.0 × 10⁻⁶ to 1.0 × 10⁻² M; a Nernstian slope of 19.7 ± 0.5 mV decade⁻¹; a detection limit of 4.4 × 10⁻⁷ M; a response time of <10 s; and use for at least 2 months without any significant potential divergence in the pH range of 3.5–8.4. Moreover, the recommended selective sensor revealed a comparatively satisfactory selectivity regarding most of the alkali and alkaline earth ions and some of the transition-metal and heavy-metal ions. In fact, it was used as an indicator electrode in the Yb(III) potentiometric titration with ethylene diamine tetra-acetic acid (EDTA) and the determination of concentration of Yb(III) ions in soil and sediment samples.

Keywords:

• Ion-selective electrode
• potentiometry
• PVC membrane
• sensor

The authors appreciate the financial support kindly offered by the Research Council of Quchan University for the completion of this research.