Cobalt phthalocyanine derivatives as neutral carriers for nitrite-sensitive poly(vinyl chloride) membrane electrodes

Abstract

PVC membrane electrodes based on cobalt phthalocyanine and its derivatives are described. An electrode that exhibits the selectivity sequence NO₂^– > SCN^–≈ I^–≫ CIO₄^– > Br^– > NO₃^– > Cl^– > OAc^– was prepared. The electrodes show a linear response towards nitrite in the range 6 × 10^–2–5 × 10^–6 mol dm^–3 with a slope of –52.0 mV decade^–1(at 20 °C). The electrode has a satisfactory reproducibility and a rapid potential response. The UV spectra of the carrier and the a.c. impedance of the membrane were studied.