Al(III) Coated Wire Selective Electrode Based on 5-Bromo(salicylidene-2-aminothiophenol) Schiff Base as a New Ionophore

A new Al(III) selective membrane based on 5-bromo(salicylidene-2-amino thiophenol) as a neutral carrier in a poly(vinyl chloride) (PVC) matrix is coated on platinum wire to determine trace amounts of Al(III) ion in various samples. The sensor exhibits a good response for Al(III) ion over a wide concentration range of 5.20 × 10-7 to 1.00 × 10-2 M  with Nernstian slope of 19.64 ± 0.15 mV decade-1 and low detection limit of 5.01 × 10-7 M. The performance of the sensor is best in the pH range of 4.00-6.50 without any divergence in potential and it also works well in partially non-aqueous medium. The coated wire electrode has a short response time of about 5 s and is stable for at least 2 months. The proposed membrane electrode revealed good selectivity for Al(III) ion over a wide variety of other metal ions. It was successfully applied for determination of Al(III) ion in different real and environmental samples and also as an indicator electrode for potentiometric titration of Al(III) ion with EDTA.