An examination of some active organometallic substances for ion-selective electrodes

Examinations of a number of possible electroactive substances for use in both liquid membrane and solid-state ion-selective electrodes were carried out. Liquid membrane electrodes incorporating organometallic salts of lead and thallium were considered as constituents of sulphate, chromate, carbonate and nitrate responsive sensors. No practically useful device was, however, found. Several electrically semiconducting metal-phthalocyanines, metal-tetracyanoethylene (TCNE) polymers and metal-coordination polymers were also synthesized and investigated with solid-state electrode constructional techniques. Metal-phthalocyanine electrodes were found to be responsive to anions rather than to cations and some anion selectivity was observed. Metal-TCNE polymer electrodes showed response to metal ions identical with those contained in the polymer, and some good selectivities, operational activity ranges and response times were found. Electrodes made from coordination polymers incorporating copper showed a limited response to copper ions whilst inclusion of cadmium and iron(III) in the polymer matrix produced an electrode with anion reponse and slight anion selectivity.