Electrochemical Oxidation of Triticonazole on Boron-Doped Diamond-Based Electrodes for Analysis of Real Matrices

Abstract

The voltammetric behavior of the triazole fungicide triticonazole (TTC) was investigated for the first time using a boron-doped diamond electrode (BDDE). TTC provides several current responses on BDDE. An irreversible first anodic peak was observed at a potential of +1.5 V (vs. Ag/AgCl/KCl, sat.), while a second indistinctive oxidation peak was observed at approximately +2.0 V in the supporting electrolyte current onset, and a reduction peak was observed at a potential of 0 V. The mechanism of TTC oxidation was proposed and supported by theoretical calculations, electrochemical measurements, and the exhaustive electrolysis accompanied with product analysis using liquid chromatography with mass spectrometry (LC/MS). Subsequently, a voltammetric method for the determination of the fungicide was developed, employing square-wave voltammetry. This method exhibited a low limit of detection (0.125 µmol L−1), a broad linear dynamic range (0.5–20 µmol L−1), and excellent recovery in the analysis of pesticide preparations. Considering the low concentrations of TTC in natural waters, a sample pre-concentration technique using solid phase extraction was developed for these applications. The novel method was successfully transferred to screen-printed sensors with BDD electrodes (SP/BDDE). The obtained results indicate that SP/BDDE enable an expansion of the linear dynamic range (0.25–60 µmol L−1) of the proposed method. SP/BDDEs were successfully applied in the analysis of pesticide formulations and demonstrated 1.68–1.85 times better sensitivity.