An inorganic gel membrane sensor for cadmium ions

Abstract

A new solid state membrane sensor has been fabricated using polytungstoantimonate as the electroactive phase. The membrane exhibits promising selectivity for cadmium which can be estimated in the range 6.31 x 10^{- 5} to 1.00 X 10^-1 <i>M </i> at <i>p</i>H 5-7 with a near Nerstian slope of 26 mV per decade of concentration. The roman potentials generated across the membrane are reproducible and the response time is less than a minute. The electrode works well even in partially non-aqueous medium. Selectivity coefficient values for various interfering ions indicate reasonably good selectivity for Cd^{2 +} ions. The electrode can also be used as an end point indicator in the titration of cadmium with EDTA.