Electrochemical and electrogravimetric studies of the deposition and catalysis of capsaicin in polyaniline: A preliminary study of the determination of chili hotness

- Electrocatalysis of capsaicin in polyaniline.
- Deposition of capsaicin in polyaniline.
- Determination of chili hotness using polyaniline.
- Influence of morphology of PANI in reaction of capsaicin.

This work involves the electrochemical and electrogravimetric studies of capsaicin (CP) on a polyaniline (PANI) electrode. The electrogravimetric experiments showed that CP is immobilized on the PANI surface when this polymer is cycled in a solution containing CP. When the potentials applied were less than the oxidation potential of CP, this molecule was weakly attached to the PANI surface and CP conserve its chemical structure. When the potential applied during the potential sweep was sufficiently high to oxidize CP, it was observed that the PANI catalyzed the reaction corresponding to the redox process of the catechol/o-benzoquinone moiety contained in the compound formed during oxidation of CP. Furthermore, the compound formed during the oxidation of CP produced an electroactive film on the PANI surface. The film formed was strongly attached to the PANI surface. Electrocatalysis and electrodeposition were more important for the PANI films of swollen morphology than those of compact structures. The Fourier transformed infrared spectra and Scaning electron microscopy corroborated the formation of the film of CP. CP film was used to its quantification. Calibration curves were based on both changes of current and changes of mass. The lowest detection limit o was 0.758 μM. Preconcentration was not necessary. Electromicrogravimetric study shows that CP films is formed also on naked Pt electrode surface, but the electrodeposition is considerably minor in comparison with those observed on PANI.