IODIDE-SELECTIVE PVC MEMBRANE ELECTRODES BASED ON 5 TRANSITIONAL METAL-CHELATES OF BIS-FURFURAL-SEMI-O-TOLIDINE

Some new PVC membrane electrodes based on Co(II), Mn(II), Ni(II), Cu(I I), and Zn(II)chelates of bis-furfural-semi-o-tolidine as carriers are described. The electrodes exhibited different selectivity behaviour c ompared with the electrode using a classical anion exchanger such as t etraalkyl ammonium. The results showed that the Cobalt(II) chelate-bas ed electrodes had a Nernstian response to iodide ion ranging from 1.0x 10(-1) to 1.0x10(6) mol.L-1 in a phosphate buffer solution of pH 2.0 w ith a detection limit of 6.4x10(-7) mol.L-1 and a slope of 57.8 mV/dec at 25 degrees C. The response mechanism was also investigated by use of both a.c. impedance and SPQC techniques. The Co(II) chelate-based e lectrodes were used to determine the iodide content of a drug with sat isfactory results.