POTENTIOMETRIC AND FIBER OPTIC SENSORS FOR PH BASED ON AN ELECTROPOLYMERIZED COBALT PORPHYRIN

Potentiometric and fiber optic sensors based on polymer films were pre pared by electrodeposition of the ion-carrier monomer cobalt(II) tetra kis (p-hydroxyphenyl)porphyrin, Co(p-OH)TPP!. Fiber optic sensors wer e developed by electropolymerization of the porphyrin on the surface o f indium (tin) oxide glass slides. The optical sensors were highly sel ective to pH, presenting minimal interferences from anions. They had a linear response from pH 8 to 12. Potentiometric sensors were prepared from porphyrin films electrodeposited on glassy-carbon disk electrode s. These electrodes gave a near-Nernstian response to pH from pH 2 to 12 with minimal interferences.