Electropolymerization of Aminoanthraquinone from H2SO4/Acetonitrile Mixed Solvent - Polymer Film Characterization and its Use as Analytical Sensor

摘要

Polyaminoanthraquinone, PAAQ, films were prepared potentiodynamically and potentiostatically from acetonitrile/sulfuric acid mixed solvent. Series of investigations have been carried out in which the mixed solvent ratio, type of substrate, electrochemical technique, potential scan range, scan rate and number of cycles were investigated in order to optimize the electropolymerization process. The potentiodynamic technique using glassy carbon, GC, substrates provides more stable films and useful information about the electropolymerization process from the mixed solvent. The suitable monomer concentration was 5.0 mM of 1-amino-9, 10-anthraquinone dissolved in 4.0M H2SO4/ACN mixed solvent with a volume ratio 7 : 3. The most suitable potential scan range was from —0.5 to +1.4V at a scan rate of 100mV s~(-1). The effect of the scan repetition i.e. the thickness of the prepared polymer films on the electroanalytical performance of the modified electrode was investigated and discussed. The kinetics of electropolymerization process was investigated and the reaction was found to be first order with respect to the monomer concentration and of negative order with respect to sulfuric acid. The formed films were used successfully as analytical sensors for ascorbic acid, catechol, Ce III ions, dopamine, epinephrine, p-aminophenol and pyrogallol. The determination is based on the construction of a calibration curve for each analyte using the values of the oxidation peak currents in the cyclic voltammogram obtained by the PAAQ modified electrode in each case. The data were compared with the data obtained previously by the same films prepared in non-aqueous and aqueous media. The significance of the analytical performance of the formed films with respect to the state-of-the-art was investigated and discussed. The use of the mixed solvent, beside its effectiveness as analytical sensor, has limited the effect of hazardous organic solvent.