Polyindole modified potassium ion-sensor using dibenzo-18-crown-6 mediated PVC matrix membrane

Abstract

A potassium ion-selective electrode using PVC matrix membrane impregnated with dibenzo-18-crown-6 at the surface of the polyindole modified electrode is reported. The electroactivity of the polyindole film contributing to the high selectivity of the neutral carrier based ion-sensor is analyzed based on the cyclic voltammetry. The polyindole modified electrode is formed by the electropolymerization of the indole monomer in dichloromethane containing tetrabutyl ammonium perchlorate (TBAP). A highly stable electroactive polyindole film is obtained. A neutral carrier impregnated PVC membrane is formed by casting over the surface of the polyindole modified electrode. The resulting ion-selective electrode without the incorporation of polyanions shows high reproducibility with negligible drift of the standard potential with a slope of 53 mV/decade. The lowest detection limit for the potassium ion sensor is 7.0 × 10-6 mol dm-3 with a wide linearity over almost five decades. A typical response of the neutral carrier impregnated PVC membrane over the polyindole modified electrode to the potassium ion is reported. © 1998 Elsevier Science S.A. All rights reserved.