Microwave-assisted synthesis of copper oxide particles and its application for determination of imazapyr in environmental samples.

Abstract

Imazapyr (IMA) is currently applied as pre- and post-emergence herbicide for control of weeds in crops. Because of its extensive use, IMA residues may reach water sources and soils. Consequently, its accurate measurement is demanded for timely actions with minimal involved steps and analysis time. Herein, copper oxide particles (Cu₂O PS) were proposed as chemical sensor for determination of IMA residues. Cu₂O PS were prepared by a facile microwave-assisted method using glucose as reducing agent and polyvinylpyrrolidone as stabilizer. The effect of main experimental parameters on the conversion rate of the Cu₂O PS were analyzed by the response surface methodology. Obtained particles were thoroughly characterized in order to determine the particle size distribution, morphology, surface charge, optical and surface properties for further application. Determination of IMA was only based on the localized surface plasmon resonance band of Cu₂O PS at 473 nm. Under optimal conditions, the method was evaluated in the concentration range between 80.0 and 1,000 μg L^-1 showing a limit of detection about 101 μg L^-1 (R² >0.98). The applicability of the proposed methodology to determine IMA in soil and water samples was assessed with satisfactory recoveries (104-121.8%) displaying a good implementation prospect in environmental complex matrices.