Flow injection photoinduced chemiluminescence determination of imazalil in water samples

Abstract

In this work, a fast, simple and economic method is proposed for the determination of imazalil in water samples by flow injection photoinduced chemiluminescence. In this method, imazalil degrades in basic media through the use of a photoreactor, and the resulting photofragments react with ferricyanide and generate the direct chemiluminescence signal. To the authors’ knowledge, this is the first time that a chemiluminescence method has been proposed for the determination of this fungicide. All physical and chemical parameters in the flow injection chemiluminescence system were optimized in the experimental setting. In the absence of preconcentration, the linear dynamic range for imazalil was 0.75–5 mg L⁻¹ and the detection limit was 0.171 mg L⁻¹. The application of solid-phase extraction with C18 cartridges allowed the elimination of interference ions, the reduction of the linear dynamic range to 15–100 μg L⁻¹, and a detection limit of 3.4 μg L⁻¹. This detection limit is below the maximum concentration level established by the Regulations of the Hydraulic Public Domain for pesticide dumping. The sample throughput after solid-phase extraction of the analyte was 12 samples h⁻¹. The intraday and interday coefficients of variation were below 9.9% in all cases. This method was applied to the analysis of environmental water samples, and recoveries of between 95.7 and 110% were obtained.