Direct determination of oxalic acid by a bare platinum electrode contrasting a platinum nanoparticles-modified glassy carbon electrode

A bare platinum disk electrode without further decoration was directly used to determine oxalic acid (OA), showing good linear ranges of 0.57-104.01 M and 104.01-228.75 M with a low detection limit of 0.38 M (S/N = 3). In contrast, platinum nanoparticles (PtNPs) dispersed on a glassy carbon electrode were successfully achieved by an one-step electrochemical deposition method, possessing relatively wider linear detection ranges of 1.14-342.80 M and 342.80-548.92 M for OA with a lower detection limit of 0.28 M (S/N = 3). Both the proposed electrochemical sensors exhibit great reproducibility, stability and selectivity. In particular, they have been applied to the determination of OA in real spinach samples, showing excellent analytical performance.