Abstract
Electrocatalytic oxidation and detection of nitrite at a carbon paste electrode chemically modified with N, N′-bis(salicylaldehyde)-4-methyl-1,2-phenylenediimino oxovanadium(IV) as a Schiff base complex ([VO(SB)]), was thoroughly investigated. Anodic oxidation of nitrite (in pH 4) at the [VO(SB)]-modified carbon paste electrode occurred at low overpotential (0.87 V versus Ag/AgCl), and treatment of the voltammetric data showed that it was a purely diffusion-controlled reaction involving one-electron in the rate-determining step. The mechanism for the interaction of nitrite with the vanadium(IV) Schiff base complex is proposed to involve the V IV(SB) 2+/V III(SB) + redox process. The modified electrode exhibits good catalytic activity for the oxidation of nitrite with good sensitivity over the wide concentration range of 3.90 × 10 −6–4.05 × 10 −3 M nitrite, and a detection limit of 6.13 × 10 −7 M ( S/ N = 3). The heterogeneous rate constant, k′, and the standard heterogeneous rate constant, k 0, for the oxidation of nitrite at the surface of the modified electrode were determined by rotating disk electrode voltammetry using the Koutecky–Levich plot. The transfer coefficient ( α) for electrocatalytic oxidation of nitrite and the diffusion coefficient of this substance under the experimental conditions were also investigated in this study.
Published Version
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