Cyclic Voltammetric and Electrochemical Simulation Studies on the Electro-Oxidation of Catechol in the Presence of 4, 4-bipyridine

Abstract

The studies were made using cyclic voltammetry on a glassy carbon electrode in aqueous solution containing phosphate buffer solution as supporting electrolyte. The purpose of the investigation was to carry out a quantitative detailed study of the electrochemical oxidation of catechol in the presence of 4, 4-bipyridine in aqueous solution. The electrooxidation of catechol produces a very reactive intermediate, o-benzoquinone, which subsequently reacts with 4, 4-bipyridine in 1, 4-Michael addition reaction to form the corresponding catechol derivative product. The kinetic data were extracted from cyclic voltammograms with the help of digital simulation. The results of the study show that catechol is oxidized in aqueous phosphate buffer solution to a very reactive intermediate o-benzoquinone.

Characterization of Electrode Performance in Enzymatic Biofuel Cells Using Cyclic Voltammetry and Electrochemical Impedance Spectroscopy

“…Generally, the current (i pa ) is proportional to the square of the scan rate (Figures 1b and 2b). The current peak separations between the bioanodic and biocathodic current peak potentials at a scan rate of 50 mV/s are higher than those at 59 mV/s, which is one of the primary indications of a quasi-reversible system according to previous work [12].…”

“…This indicates that a chemical reaction occurred between the GOx and its combinations (carbon nanotubes (CNT), M, and polypyrrole (PPY)), as occurred for LAc, too. These observed phenomena were studied extensively in previous work [12][13][14]. According to Figures 1 and 2, the cyclic voltammograms show the shifting of the anodic and cathodic peak potentials with an increasing trend, which indicates efficient mass transfer between the electrodes, and the oxidation and reduction of the enzyme were best achieved with the CNT combination since it has good electrical conductivity.…”

“…From the results, it can be concluded that GOx-M-CNT and LAc-M-CNT are the best electrodes, whose diffusion coefficients are better in the CNT combination for both GOx (9.2 × 10 −6 cm 2 /s) and LAc (9.0 × 10 −6 cm 2 /s), as shown in Table 1 [12]. Moreover, the blank carbon paper electrode shows little material diffusion or low conductivity because there were no essential supporting materials such CNT and mediators to aid this effect and, hence, a low diffusion coefficient (7.02 × 10 −6 cm 2 /s) resulted, as shown in Table 1.…”

Carbon dots functionalized papers for high-throughput sensing of 4-chloroethcathinone and its analogues in crime sites

“…Like most reported C-dots [45], they are quite stable against salt (up to 1.0 M NaCl) and photoirradiation (less than 20% PL change under irradiation from a light with intensity of 3 W at 365 nm for 2 h). Over pH values from 5.0 to 11.0, 4-chloroethcathinone (25.0 mM) induced PL quenching of C-dots increases upon increasing pH value, mainly because of increases in its oxidation strength [46,47]. Figure 2 a displays that 4-chloroethcathinone-induced PL quenching of C-dots at pH 11.0 increases upon increasing its concentration up to 25.0 mM.…”

In Situ Deactivation of Catechol-Containing Adhesive Using Electrochemistry

“…An alternative approach to tune the oxidation state of catechol is through electrochemical oxidation. Various studies have demonstrated the electrochemical oxidation of soluble catechol derivatives using cyclic voltammetry technique in a three-electrode electrochemical cell. − Electrochemical-induced oxidation and curing of catechol-containing adhesive was only demonstrated very recently. , Also, tuning the oxidation state of catechol by electrochemistry was used in controlling the movement of a hydrogel actuator . Additionally, direct electrochemical oxidation of catechol-functionalized coatings was used to promote cell attachment and peptide immobilization through oxidation-induced cross-linking. , However, to our knowledge, there is no direct evidence that correlated the effect of in situ electrochemical oxidation on the adhesive property of catechol.…”