Poly(vinyl chloride) matrix membrane pH electrode based on 4,4′-bis[(N,N-dialkylamino)methyl]azobenzene with a wide linear pH response range

Abstract

A poly(vinyl chloride)(PVC) matrix membrane pH electrode based on a neutral carrier containing tertiary amino and azo groups is described. It has excellent pH response characteristics with a much wider linear response range (1.7–13.2) than those of similar PVC pH sensors reported so far. The sensor has a theoretical Nernstian response slope of 57.4 ± 0.2 mV pH^–1(at 20 °C) without a super-Nernstian response phenomenon. The a.c. impedance spectra of electrode membranes incorporating an ionophore were also studied.