Electroactive species-doped poly(3,4-ethylenedioxythiophene) films: enhanced sensitivity for electrochemical simultaneous determination of vitamins B2, B6 and C

Herein, functionalized PEDOT films were prepared by incorporation of two electroactive species, ferrocenecarboxylic acid (Fc^-) and ferricyanide (Fe(CN)₆ ^4-) as doping anions during the electropolymerization of PEDOT at glassy carbon electrodes (GCEs) from aqueous solution. The electrochemically synthesized electroactive species-doped PEDOT films have been carefully characterized by scanning electron microscopy (SEM), FTIR and UV/Vis spectra and various electrochemical techniques. Such nanostructured films combined the advantages of PEDOT (high conductivity and stability) together with electroactive species (good electrochemical activity) and were applied as electrochemical sensors for simultaneous determination of vitamin B₂ (VB₂), vitamin B₆ (VB₆) and vitamin C (VC). The results showed that the oxidation peak currents of vitamins obtained at the GCEs modified with electroactive species-doped PEDOT films were much higher than those at the ClO₄ ^--doped PEDOT films and bare GCEs. The experiment results also illustrated that the sensors possessed high selectivity with no interference from other potential competing species. Moreover, the proposed sensors were successfully employed for the determination of vitamins in orange juice samples with satisfactory results.