Simultaneous microextraction of carbendazim, fipronil and picoxystrobin in naturally and artificial occurring water bodies by water-induced supramolecular solvent and determination by HPLC-DAD

Carbendazim, fipronil and picoxystrobin are pesticides widely utilized worldwide to enhance yield, improve quality and maximize economic returns of several cultures. However, due to potentially adverse effects to health and to ecosystems, their detection and monitoring in waters became a major concern. In this report, a new supramolecular solvent-based microe xtraction method, constituted of reverse micelles of 1-decanol arranged into a tetrahydrofuran/water medium, was developed to preconcentrate and monitor those pesticides in several natural and artificial waters by determination with High-Performance Liquid Chromatography - Diode Array Detector (HPLC-DAD). A 2(6-1) fractional factorial design with central point and Derringer-Suich desirability function were utilized to optimize the microextraction conditions. High preconcentration factors (21.43 to carbendazim, 71.10 to fipronil and 71.36 to picoxystrobin) and extraction factors (21.45 to carbendazim, 84.47% to fipronil and 83.00% to picoxystrobin) were obtained. The limits of detection (LOD), quantification (LOQ), the precision (RSD-relative standard deviation) and the accuracy (RE-relative error) of the developed method ranged between 0.23 and 0.45 mu g L-1, 0.78-1.50 mu g L-1, 1.65-6.53% and 0.11-6.00%, respectively. Recovery values obtained by applying the proposed method in spiked atmospheric water, groundwater, surface water and artificial water samples at mu g L-1 levels varied in the range of 93.5-110.0%. The quantification of fipronil in a natural sample water, in values higher than established by some international guidelines, reassures the importance of investigating and monitoring pesticides in natural and artificial waters. (C) 2019 Published by Elsevier B.V.