Design of Schiff base complexes of Co(II) for the preparation of iodide-selective polymeric membrane electrodes

The response characteristics of some iodide-selective solvent polymeric mem brane electrodes based on with N,N'-bis(salicylaldehyde-n-octyl) diimine co balt(II) (Co(II)SAODI) which is a more lipophilic substitute for a previous ly reported iodide-carrier are described. The electrode doped with Co(II)SA ODI into a plasticized poly(vinyl chloride) membrane exhibits an anti-Hofme ister selectivity pattern with high selectivity toward iodide, long lifetim e and small interference from H+. Quartz crystal microgravimetric measureme nts and ac impedance experiments show that the excellent selectivity for io dide is related to the unique interaction between the carriers and iodide a nd steric effect associated with the structure of the Schiff base ligands. (C) 1999 Elsevier Science B.V. All rights reserved.