An ecologically correct electroanalytical method to determine the herbicide Picloram in Amazon waters using a miniaturized boron-doped diamond electrode and a 3D compact electrochemical cell

Abstract

In this work, voltammetric methods were applied using a boron-doped diamond electrode (BDD) to detect Picloram (PCR), a very toxic and persistent herbicide. The method was applied to investigate environmental waters in the Amazon. In this context, an environmental-friendly method was developed using a miniaturized BDD electrode, and a compact electrochemical cell manufactured by a 3D printer using a polylactic acid biodegradable polymer to reduce the generated residue, leading to more sustainable research procedures with potential to be applied in field analysis. In addition, studies were carried out to establish the rate-limiting step of the reaction and the number of electrons and protons involved, being three protons and three electrons suggested for PCR electrochemical oxidation. For analytical purposes, the optimization of the square wave voltammetry (SWV) parameters and tests of precision, accuracy and sensitivity were performed. Thus, a low detection limit of 390 nmol L−1 and values for the intra-day and inter-day repeatability tests of 8.65% and 4.64%, respectively, were obtained. Due to its biodiversity abundance, environmental waters in the Amazon should be better monitored and this method can contribute to this task quite efficiently.