SUBSTITUTED COBALT PHTHALOCYANINE COMPLEXES AS CARRIERS FOR NITRITE-SENSITIVE ELECTRODES

A new poly(vinyl chloride) membrane electrode based on lipophilic 2,9, 16,23-tetra-tert-butylphthalocyanine is described which demonstrates e xcellent selectivity toward the nitrite ion. The resulting electrodes displayed a near-Nernstian response for nitrite in the concentration r ange 10(-5)-0.1 M with the selectivity sequence nitrite > thiocyanate > iodide > perchlorate > bromide > nitrate > chloride. The UV/Vis spec tra and a.c. impedance studies showed that the excellent selectivity f or nitrite was related to the unique interaction between the central c obalt ion and nitrite.