A Fast Response Strontium(II) Selective Polymeric Membrane Sensor Based on 1–Benzothiazol–3–Benzoyl–Thiocarbamide as Neutral Carrier

A new selective strontium(II) PVC membrane sensor based on the 1-benzothiazol-3-benzoylthiocarbamide (BTBTA) ligand as neutral ionophore has been developed. The sensor exhibits Nernstian potential linear range to Sr²⁺ from 4.0 × 10⁻⁷ mol/L to 1.0 × 10⁻¹ mol/L with a detection limit of 2.5 × 10⁻⁷ mol/L and a slope of 30.1±0.1 mV/decade of activity in a pH range of 3.0–8.0. It showed a response time of less than 10 s and could be used for at least 3 months without any considerable divergence in potentials. The proposed sensor showed a good discriminating ability towards strontium(II) ion over a wide variety of other metal ions including alkali, alkaline earth, transition and heavy metal ions. The response mechanism was discussed in view of the AC impedance and UV-visible spectroscopic techniques. It was used as an indicator electrode in potentiometric titration of strontium ion against EDTA. At the same time the sensor was successfully applied to the determination of strontium ions in soil and tea.