Study of Electrochemical Oxidation and Quantification of the Pesticide Pirimicarb Using a Boron-Doped Diamond Electrode

- A complete electro-oxidation mechanism of the pesticide Pirimicarb was proposed.
- The electrochemical mechanism was supported by voltammetry techniques and mass spectrometry data.
- An electroanalytical method using boron-doped diamond electrode was proposed to quantify Pirimicarb in natural waters.
- The proposed analytical method is simple, low-cost, accurate and portable.

An electrochemical study of the carbamate pesticide pirimicarb (PMC), which acts on the central nervous system, was performed using a boron-doped diamond working electrode. Cyclic, differential pulse, and square-wave voltammetry experiments across a wide pH range (2.0 to 8.0) showed three irreversible oxidation processes in the voltammetric behavior of PMC. The two first processes were pH-dependent, while the third was not. The three oxidation process were independent of each other, and each involved the transfer of one electron. A reaction proposal for the electrochemical oxidation of PMC is shown, and it is supported by mass spectrometry experiments. After this, an analytical method for PMC quantification in water samples by differential pulse (DP) voltammetry is proposed. The optimal DP voltammetric parameters (step potential, amplitude potential, and scan rate) were optimized using experimental design, and an analytical curve was obtained from 2.0 to 219 μmol L−1 with an estimated detection limit of 1.24 μmol L−1. The accuracy of the proposed method was evaluated by the addition and recovery method, with recoveries ranging from 88.6 to 96.3%. Some highlights of the proposed analytical method are its simplicity, reliability, and portability.