Potentiometric anion response of poly (tetrakis(p-aminophenyl)porphyrin) film-modified electrodes

✍ Scribed by Dennis M. Kliza; Mark E. Meyerhoff

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 830 KB
• Volume: 4
• Category: Article
• ISSN: 1040-0397
• DOI: 10.1002/elan.1140040904

✦ Synopsis

The potentiometric response to anions of glassy carbon electrodes coated with thin unmetallated poly(tetrakis( p-aniinopheny1)porphyrin) (poly(H,( p-TAPP))) films is examined. The polymer films are introduced onto the glassy carbon surface by constant-potential anodic electrolysis of the porphyrin monomer from a solution of dichloromethane containing a quaternary ammonium perchlorate salt. The thickness of the film is controlled by the electrodeposition time. Oxidized polp(porphyrin) modified electrodes exhibit near Nernstian response to iodide in the concentration range of 5 X -1 x lo-' M with significant selecrivity over a wide range of other anions tested. The mechanism of the electrode's iodide ion response is considered in light of its response to other redox-active anions, and a recent literature report describing the selective iodide response of electrodes coated with electropolymerized poly(3-methylthiophene) films. Spectroelectrochernical studies with poly(porphyri1i)-modified tin oxide electrodes are used to confirm the redox-type response mechanism of the sensors toward iodide. The analytical limitations of using such polymer filmmodified electrodes for potentiometric ion sensing are discussed.