Solid-phase microextraction for determination of anilino-pyrimidine, dimethylcarbamate and thiadiazine pesticides in irrigation project surface water

Abstract

The objective of this work was to develop a solid-phase microextraction (SPME) technique for the determination of residues of the pyrimethanil, pirimicarb and buprofezin pesticides in surface waters from irrigated areas, with analysis by gas chromatography-mass spectrometry (GC-MS). The optimized method used a 100 µm polydimethylsiloxane (PDMS) fiber, agitation speed of the sample of 900 rpm and pH 7.0. Extraction and desorption times were 30 and 7 min, respectively. Linearity was achieved in the concentration range 0.1-4.0 µg L-1, and coefficients of determination (R²) were > 0.991. Precision, expressed as relative standard deviation (RSD), was < 15%, and limits of detection (LOD) and quantification (LOQ) were in the ranges 0.04-0.1 µg L-1 and 0.1-0.2 µg L-1, respectively. Surface water samples were collected from irrigated regions of the Platô de Neópolis in Sergipe State (Brazil) and from Distrito de Irrigação Senador Nilo Coelho in Pernambuco State (Brazil). Concentrations of buprofezin were < 0.14 µg L-1, while those of pirimicarb were lower than the limit of quantification (LOQ). Pyrimethanil was not detected in the samples.