Anion-selective membrane electrodes based on polymer-supported metalloporphyrins

Prepared polystyrene pyridine copolymer supported manganese(III) protoporph yrin IX structures (MnPPIX-PSP4) were applied as an ionophore for ion selec tive electrodes. The responses of the solvent/polymeric membrane based on M nPPIX-PSP4 with standard PVC composition (NPOE as plasticizer: PVC: estimat ed ionophore in polymer = 132:66:2.6) were measured. The membranes based on MnPPIX-PSP4 exhibited not only excellent selectivity to iodide ion compare d to other anions examined, but also Nernstian behavior (58 mV dec(-1)). Th e optimization of the experimental conditions for potentiometric analysis o ffers a wide linear dynamic range (10(-1) to 10(-5) M I-), reasonable detec tion limits(similar to 10(-5) M) and good durability within a limited error . The anion selective solvent/polymeric membranes based on polymer supporte d metalloporphyrins could overcome the shortcomings of limited life time, d ue to the loss of ionophores to the solution without effects from the high resistance of membranes. This is the first report that the addition of only around 1% of a polymer-attached ionophore into a plasticized PVC membrane leads to selectivity of salicylate due to the size exclusion effect. (C) 19 99 Elsevier Science S.A. All rights reserved.