Premium
Potentiometric anion response of poly (tetrakis( p ‐aminophenyl)porphyrin) film‐modified electrodes
Author(s) -
Kliza Dennis M.,
Meyerhoff Mark E.
Publication year - 1992
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.1140040904
Subject(s) - porphyrin , iodide , inorganic chemistry , potentiometric titration , glassy carbon , electrode , chemistry , redox , perchlorate , cyclic voltammetry , electrochemistry , materials science , photochemistry , ion , organic chemistry
The potentiometric response to anions of glassy carbon electrodes coated with thin unmetallated poly(tetrakis( p ‐aminophenyl)porphyrin) (poly(H 2 (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 the controlled by the electrodeposition time. Oxidized poly(porphyrin) modified electrodes exhibit near Nernstian response to iodide in the concentration range of 5 × 10 −5 – 1 × 10 −1 M with significant selectivity 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. Spectroelectrochemical studies with poly(porphyrin)‐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 film‐modified electrodes for potentiometric ion sensing are discussed.