FABRICATION OF A MULTILAYER FILM ELECTRODE CONTAINING PORPHYRIN AND ITS APPLICATION AS A POTENTIOMETRIC SENSOR OF IODIDE-ION

A novel iodide ion-selective electrode has been produced based on a mo lecular deposition technique in which water-soluble porphyrin was alte rnatively deposited with water-soluble polypyrrole on a 2-aminoethanet hiol modified silver electrode. The potentiometric response is indepen dent of pH of the solution between pH 1 and 7, while it is dependent o n the nature of the medium. The electrode has a linear dynamic range b etween 1.6 x 10(-6) and 0.1 M with a Nernstian slope of 59 mV/decade a nd a detection limit of 1.0 x 10(-6) M in acetate buffer (0.1 M, pH 4. 6). The electrode has the advantages of low resistance, short conditio ning time and fast response. (C) 1998 Elsevier Science B.V. All rights reserved.