Erbium(III) PVC Membrane Ion-Selective Sensor based on 4-(2-Thiazolylazo)resorcinal

Abstract

4-(2-Thiazolylazo)resorcinol (TR) was used as a new compound to play the role of an excellent ion carrier in the fabrication of an Er(III) membrane electrode. The electrode shows a very good selectivity toward Er(III) ions over a wide variety of cations, including alkali, alkaline earth, transition, and heavy-metal ions. The proposed sensor exhibits a Nernstian behavior (with slope of 19.6 ± 0.6 mV per decade) over a wide concentration range (1.0 × 10⁻⁶ to 1.0 × 10⁻² M). The detection limit of the sensor is 6.6 × 10⁻⁷ M. It has a very short response time, in the whole concentration range (∼10 s), and can be used for at least 12 weeks in the pH range of 2.8–9.3. The proposed sensor was successfully applied as an indicator electrode for the potentiometric titration of a Er(III) solution, with EDTA. It was also successfully applied to the F⁻ ion determination in some mouthwashing solutions.

Keywords:

• Ion-selective electrode
• potentiometry
• PVC membrane
• sensor
• 4-(2-Thiazolylazo)resorcinol

The authors acknowledge the kind financial support provided by the Research Council of Quchan University for the preparation of this study.

Notes

NM: Not mentioned.

^a Proposed Er³⁺ sensor.

^b Results are based on three measurements.