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In this study, a green and effective ultrasound-assisted dispersive liquid-liquid microextraction method based on a hydrophobic deep eutectic solvent (UA-DLLME-DES) was developed for the preconcentration and determination of pyrethroid insecticides (deltamethrin, fenvalerate, permethrin, etofenprox, and bifenthrin) in environmental water samples using high-performance liquid chromatography combined with an ultraviolet detector (HPLC-UVD). Hydrophobic deep eutectic solvents (DESs) are green solvents prepared by mixing quaternary phosphonium salts and straight-chain monobasic acids. DESs were synthesized and characterized by Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA). Several key parameters, including the types and amounts of DESs, pH value, sample volume, ultrasound time, salt addition, and centrifugation rate and time, were researched and optimized. Under the optimal experimental conditions, the proposed method required only a small amount of DES to complete extraction and recovery in a very short time. The validated method showed good linearity, with a coefficient of determination (R2) ranging from 0.9992 to 0.9995, and good repeatability, with relative standard deviations (RSDs) ranging from 1.45 to 4.86%, for all analytes. The limits of detection (LODs) varied from 0.30 to 0.60 μg/L. Finally, the presented method was implemented to determine the pyrethroid insecticides in environmental water samples, and acceptable recoveries within the range of 80.93–109.88% were obtained.

A magnetic Metal-Organic Frameworks composite material modified with attapulgite was prepared via in situ growth method and characterized by Fourier transform infrared, X-ray diffraction, scanning electron microscopy, N2 adsorption-desorption and vibration sample magnetometer analysis. It was applied as an efficient adsorbent for the magnetic solid-phase extraction of seven benzoylurea insecticides from environmental water samples couple with high-performance liquid chromatography detection. Under the optimized experimental conditions, the established procedure exhibited low limit of detection ranging from 0.75 to 1.5 µg L−1 and good linear response ranging from 2.5 to 500 µg L−1 with coefficients of determination >0.99. The method recoveries of spiked analytes at the concentrations of 20, 100 and 200 µg L−1 in real water samples were 73.56–99.63% with the relative standard deviations

A facile synthetic method of attapulgite@covalent organic frameworks was reported in this study. The composite was synthesized by covalently grafting covalent organic frameworks (synthesized from 1,3,5-triformylphloroglucinol and p-phenylenediamine) onto attapulgite at room temperature and was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, zeta potential analysis, transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller measurement. The synthesized nanocomposite was used as a sorbent in dispersive solid phase extraction to extract pyrethroids from environmental water samples, and the parameters affecting the extraction efficiency were optimized. The linear range of the four pyrethroids was 2.5–500 μg L−1, and the enrichment factors ranged from 65.0 to 68.2. The method detection limits were between 0.83 and 1.79 μg L−1 under the optimal conditions. In addition, the intra-day and inter-day precision were 1.4%–4.8% and 2.7%–3.6%, respectively. Finally, the method was successfully applied to extract pyrethroids from real water samples with relative recoveries ranging from 71.2% to 88.7%.

A method was developed using dispersive solid-phase extraction based on hyperbranched polymer functionalized with β-cyclodextrin for extraction and enrichment of three pyrethroid pesticides (fenpropathrin, cyhalothrin, and ethofenprox) in environmental water samples before high-performance liquid chromatography analysis. The aim of this research was to establish a simple, high-speed, effective, and sensitive method for the detection of target analytes. The as-prepared sorbents were synthesized successfully, and characterized by scanning electron microscopy, energy dispersive spectroscopy, elemental analysis, Brunauer-Emmett-Teller measurement and Fourier transform infrared spectroscopy. The experimental factors influencing the extraction efficiency such as extraction time, pH, ionic strength, desorption conditions, etc. were optimized. Good linearity was observed for all three pyrethroids, and the linear range of fenpropathrin was 10–500 ng/mL, and cyhalothrin, ethofenprox were 5–500 ng/mL. The method detection limits were ranged from 1.0 ng/mL to 2.1 ng/mL under the optimal conditions. The recoveries achieved ranged from 83.1% to 91.6% for the extraction of the three target analytes. Apart from these, the relative standard deviation (intra-day and inter-day) were measured fewer than 6.0%. The method in this work was applied to the rapid enrichment and detection of pyrethroids in environmental water samples.