DPASV detection of metribuzin using the cathodic pretreated boron-doped diamond electrode

Abstract

Abstract The widespread use of the triazinone herbicide metribuzin (MTZ) demands reliable, rapid, and cost-effective analytical methods for environmental monitoring. In this work, we report, for the first time, the electroanalytical determination of MTZ based on its anodic behavior at a boron-doped diamond (BDD) electrode. The method exploits a differential pulse anodic stripping voltammetry (DPASV) approach, in which MTZ undergoes a preconcentration step via electrochemical reduction, followed by oxidation of the generated intermediate. The influence of surface pretreatment was systematically evaluated, demonstrating that cathodically pretreated BDD (BDD-CTP) significantly enhances electron-transfer kinetics and analytical sensitivity due to hydrogen-terminated surfaces characteristics. The electrochemical oxidation process was found to be irreversible, diffusion-controlled, and governed by a two-electron/two-proton mechanism, with a heterogeneous rate constant of 1.5 s ‒1 . Under optimized conditions ( E ac = ‒0.60 V, t ac = 60 s, pH 2.0), the method exhibited a linear response in the concentration range of 1.31 – 12.4 µmol L ‒1 ( R 2 = 0.9994), with a limit of detection ( LOD ) of 0.17 µmol L ‒1 . The sensor demonstrated excellent repeatability (RSD ≤ 2.7%) and good selectivity in the presence of common inorganic interferents. The applicability of the method was successfully demonstrated in environmental water samples (tap and river water), yielding satisfactory recoveries (100–106%) Compared to conventional reductive approaches, the proposed anodic strategy provides complementary mechanistic insight while avoiding limitations associated with electrode fouling and narrow potential windows. These findings highlight the potential of BDD electrodes as robust and versatile platforms for herbicide MTZ in environmental matrices. Graphic abstract Schematic representation of the electrochemical detection of MTZ in sugarcane and soybean matrices using a hydrogen-terminated boron-doped diamond electrode, highlighting the oxidation process and circular economy framework.