Applicability of Electroanalysis for Monitoring Oxalic Acid (OA) Concentration During its Electrochemical Oxidation at Different Electrode Materials

Sensitive electrochemical determination of oxalic acid in spinach samples by a graphene-modified carbon ionic liquid electrode

“…The detection limit was estimated to be 0.48 μM (S/N=3), which was calculated by the equation: C L =KS o /S, where C L is the detection limit, K is a constant related to the confidence level, according to the suggestion of IUPAC, K=3 (99 % confidence), S o is the standard deviation of the blank measurements (N=9) and S is the slope of the calibration curve. The result was smaller than the previous reported values of 6.2 μM by HPLC [2], 0.2 mM on palladium nanoparticleloaded carbon nanofiber composites-modified carbon paste electrode (Pd/CNF-CPE) [7], 0.09 mM on a bienzymatic amperometric biosensor [9], 12.0 μM on MWCNT/GCE [14], 0.51 mM on GCE [17] and 0.05 mM on graphitepolystyrene composite electrode [37].…”

“…GR has exhibited many specific properties such as high surface area, good electrochemical conductivity and excellent electrocatalytic ability, which can increase the electron transfer rate and decrease the overpotential. Electrochemical oxidation of OA had been investigated on different kinds of working electrode or chemically modified electrode [16][17][18]. Due to the various electrode interfaces, the oxidation potential differs greatly in different references.…”

“…Ferro et al investigated the electrooxidation of OA on different electrode materials [16]. Pinizza et al also studied the electrochemical oxidation of OA at different electrode materials [17]. Ferreia et al investigated the electrocatalytic oxidation of OA in aqueous media at carbon nanotube-modified electrode loaded with monometallic or bimetallic catalysts [18].…”

“…The electrochemical oxidation of OA at different electrode materials has been reported [11][12][13][14][15][16][17][18]. But to the best of our knowledge, there is no report on OA oxidation and determination using a GR-modified CILE, which exhibits attractive performances for the sensitive OA detection with excellent voltammetric response.…”

Cysteic Acid‐Modified Glassy Carbon Electrode for Monitoring Oxalic Acid (OA) Concentration During Its Electrochemical Oxidation at Ti/Pt Anode

“…Based on these assumptions, the plateau formed after elimination about 80 % of OA, is due to the deactivation of active sites on Pt surface (oxidized Pt surface: PtÀOHC!PtÀOC + H + + e) involving most probably the oxygen evolution reaction as the main process (2PtÀOC! 2M + O 2 ), limiting the adsorption of OA molecules as well as hydroxyl radicals, at active Pt sites, for completing OA elimination (PtÀOHC + PtÀHC 2 O 4 C!2Pt + 2CO 2 + H 2 O) [21].…”