Potentiometric pH sensors based on chemically modified electrodes with electropolymerized metal-tetraaminophthalocyanine.

Potentiometric pH sensors based on polymer film were prepared by electropolymerization of the monomer nickel(II)-4,4',4'',4'''-tetraaminophthalocyanine (NiTAPc) or copper(II)-4,4',4'',4'''-tetraaminophthalocyanine (CuTAPc) on glassy carbon (GC) electrodes. The polymer of metal tetraaminophthalocyanine (p-MTAPc) film coated electrodes show a slope of 55 +/- 1 mV/pH (at 20 degrees C) and nearly Nernstain potentiometric response to pH over the range of pH 1-13. The electrodes possess good potential reproducibility and high selectivity, and are useful sensing devices in pH determination and end-point indication of acid-base potentiometric titration.