Electrochemical reactions of catechol, methylcatechol and dopamine at tetrahedral amorphous carbon (ta-C) thin film electrodes

The electrochemical reactions of dopamine, catechol and methylcatechol were investigated at tetrahedral amorphous carbon (ta-C) thin film electrodes. In order to better understand the reaction mechanisms of these molecules, cyclic voltammetry with varying scan rates was carried out at different pH values in H2SO4 and PBS solutions. The results were compared to the same redox reactions taking place at glassy carbon (GC) electrodes. All three catechols exhibited quasi-reversible behavior with sluggish electron transfer kinetics at the ta-C electrode. At neutral and alkaline pH, rapid coupled homogeneous reactions followed the oxidation of the catechols to the corresponding o-quinones and led to significant deterioration of the electrode response. At acidic pH, the extent of deterioration was considerably lower. All the redox reactions showed significantly faster electron transfer kinetics at the GC electrode and it was less susceptible toward surface passivation. An EC mechanism was observed for the oxidation of dopamine at both ta-C and GC electrodes and the formation of polydopamine was suspected to cause the passivation of the electrodes.

Panoràmica de la folklorística valenciana: autors, períodes, textos i contextos

En aquest estudi es fa un repàs a la història de la folklorísica valenciana a través de quatre períodes. Entre 1873 i 1912, la recol·lecció folklòrica està encara molt lligada a la creació literària. Entre 1912 i 1939, s’hi poden trobar els primers intents d’institucionalització i l’emancipació del folklore com a disciplina. Durant el franquisme, de 1939 a 1975, es truncarien molts esforços previs, encara que apareixerien figures individuals rellevants i interessants campanyes per al folklore musical. Finalment, des de 1975 a l’actualitat s’observa un gran salt qualitatiu i quantitatiu pel que fa a la recol·lecció i la recerca folklòrica.