HIGHLY SELECTIVE IODIDE POLY(VINYL CHLORIDE) MEMBRANE-ELECTRODE BASEDON A NICKEL(II) TETRAAZAANNULENE MACROCYCLIC COMPLEX

A PVC membrane electrode based on a nickel(II) tetraazaannulene macroc yclic complex as the carrier is described. The electrode exhibits an a nti-Hofmeister selectivity sequence with a preference for iodide at pH 3.0-4.0. It has a linear response to iodide from 8.0 x 10(-6) to 1 x 10(-1) mol dm(-3) with a slope of -54.7 +/- 0.2 mV per decade (20 degr ees C), a satisfactory reproducibility and a rapid response time. The pH dependence of the potential response is discussed. The response mec hanism of the electrode was investigated by ac impedance, quartz cryst al microbalance and spectroscopic techniques. The electrode can be use d for the determination of iodide in drug preparations.