ELECTROPOLYMERIZATION OF PYRROLE-2-CARBOXYLIC ACID AND 4,4'-DIHYDROXYBENZOPHENONE ON PLATINUM-ELECTRODES - APPLICATIONS TO ASSEMBLE NOVEL GLUCOSE SENSORS

The electropolymerization of pyrrole-2-carboxylic acid (PY-2-COOH) and of 4,4'-dihydroxybenzophenone (DHB) has been carried out on Pt electr odes by scanning the potential from +0.4 V to +1.4 V (vs. SCE) for PY- 2-COOH and from 0.0 V to +0.8 V (vs. SCE) for DHB, at scan rate of 2-5 mV/s, in phosphate buffer (PBS) pH 8. To test the permselectivity of these polymers, cyclic voltammograms of H2O2, ascorbic acid (AA), uric acid (UA) and acetaminophen (APAP) were carried out and results were compared with those obtained at the bare electrode. The electropolymer ization in the presence of glucose oxidase was also carried out. The p robes were then tested as glucose sensors. Glucose was detected, by am perometric measurements at +0.6 V (vs. SCE). The linear response to gl ucose was in the range 7 x 10(-6)-1.8 x 10(-3) mol/L, for the sensor p repared with PPY-2-COOH and 4 x 10(-6)-2 x 10(-3) mol/L, for the senso r prepared with PDHB. The detection limit was 5 x 10(-6) mol/L for PPY -2-COOH and 2 x 10(-6) mol/L for PDHB. The response time of both polym ers was 3-5 s. The stability of the electropolymerized films and the g lucose probes was evaluated, in storage and operational conditions The glucose probes, stored in buffer at 4 degrees C when not in use, show ed a residual enzyme activity of 50%, after about two months.