Novel triiodide ion-selective polymeric membrane sensor based on mercury-salen

A triiodide ion-selective PVC membrane sensor based on a mercury-salen-bis (salicylaldehyde) ethylendiamine mercury(II) complex (MS) as a novel sensing material is successfully developed. The sensor possesses the advantages of very low detection limit (2.0×10−8 M), very wide working concentration range (5.0×10−8 to 10×10−2 M), Nernstian behavior (slope of 59.0±0.5 mV per decade), low response time (<15 s), wide pH-independent range (2.0-11.0) and, specially, high triiodide selectivity over a wide variety of other anions. The electrode was used as an indicator electrode in potentiometric titration of triiodide ions with mercury(II) ions, and vice versa.