A new aluminum(III)-selective potentiometric sensor based on N,N′-propanediamide bis(2-salicylideneimine) as a neutral carrier

This work describes the fabrication of a selective polymeric membrane potentiometric sensor for Al3+ ion based on N,N′-propanediamide bis(2-salicylideneimine) (NPBS) as a neutral carrier. The proposed sensor, with optimum membrane composition, exhibited an excellent near-Nernstian response for Al3+ ion ranging from 7.9 × 10− 7 to 1.0 × 10− 1 mol/L with a detection limit of 4.6 × 10− 7 mol/L and a slope of 19.4 ± 0.3 mV/dec in pH 3.0 nitrate solution at 25 °C. It showed a relatively fast response time (8 s), suitable reproducibility and stability, and good selectivity towards Al3+ ion. The operational pH range of the proposed sensor was 2.5–4.0. The response mechanism was discussed in view of UV–visible spectroscopy and the alternating current (AC) impedance technique. In addition, the proposed sensor was successfully used as an indicator electrode in potentiometric titration of Al3+ ion and in the direct determination of Al3+ ion in real samples.