Construction of a New Aluminum(III) Cation Selective Electrode Based on 12-Crown-4 as an Ionophore

This article describes the fabrication of a novel and selective polyvinylchloride (PVC) membrane potentiometric sensor for Al3+ cation based on 12-crown-4 (12C4) as an ionophore. The electrode was prepared by coating the surface of a graphite rod by a membrane containing PVC as a plastic matrix, dibutylphthalate (DBP) as plasticizer, 12C4 as an ionophore and oleic acid (OA) as an additive. Under optimized membrane composition, the constructed electrochemical sensor exhibited a Nernstian response for Al3+ cation concentration, ranging from 1.0 x 10(-6) to 1.0 x 10(-1) mol L-1 with a detection limit of 5.5 x 10(-7) mol L-1 and a slope of 19.0 +/- 0.4 mV per decade at 25 degrees C. The constructed potentiometric sensor showed a relatively fast response time (15 s), good reproducibility and stability, and high selectivity towards Al3+ cation in solutions. The proposed sensor was successfully used as an indicator electrode in potentiometric titration and also in the direct determination of this metal cation in real samples.