NADES-assisted dispersive liquid-liquid microextraction with solidification of floating organic drop for biopesticide determination in environmental waters

The principles of green analytical chemistry recommend the use of less polluting and more sustainable solvents, as well as extraction techniques that require minimal sample size and solvent consumption. In this study, the extraction of multi-class biopesticides from water samples was studied using more sustainable solvents such as natural deep eutectic solvents (NADES). A novel dispersive liquid-liquid microextraction method based on the solidification of floating organic drop (DLLME-SFOD) was used, employing 1-dodecanol as the extraction solvent and choline chloride:urea:water (ChClUH, molar ratio 1:2:3) as the NADES-based dispersive solvent. The extraction procedure was optimized through an experimental design, which yielded optimal conditions of 120 μL of 1-dodecanol, 1.8 mL of ChClUH, 0.5 g of amount of salt (Na 2 SO 4 ), and an extraction time of 20 min. Biopesticides determination was performed using ultra-high-performance liquid chromatography (UHPLC) and gas chromatography (GC) coupled to high resolution mass spectrometers (quadrupole (Q)-Orbitrap). Under these conditions, biopesticides such as pyrethrins, rotenone, and some monoterpenes such as 1,8-cineole exhibited low limits of quantification (LOQ, 1–25 μg/L), recoveries between 70.9 and 109.1 %, and suitable precision values of 1.8–15.8 % (intra-day) and 3.9–18.1 % (inter-day). The extraction method proved to be efficient, reproducible, and greener, as confirmed by multiple green analytical metrics. Analysis of eight water samples from different sources such as environmental water (groundwater, spring, etc.) or irrigation water confirmed the absence of target biopesticides in all cases. These results demonstrate the potential of NADES-assisted DLLME-SFOD as a sustainable and effective tool for the monitoring of biopesticides in environmental water samples. • 16 biopesticides were extracted from water using NADES-assisted DLLME-SFOD. • Hydrophilic NADES based on choline chloride, urea and water was selected.. • Design of experiments reduces the analyses performed in the optimization • Green metrics demonstrated the sustainability of the proposed method. • The method was applied to analyze different environmental water samples.