Fatty acid/alcohol-based hydrophobic deep eutectic solvents (DESs) have been considered to be eco-friendly alternatives to replace conventional hydrophobic organic solvents (i.e., halogenated solvents). These novel eco-friendly solvents are applied in the extraction and determination of two antibiotics (levofloxacin, LOF; ciprofloxacin, COF) in environmental water by liquid-liquid microextraction (LLME). Two different families of hydrophobic DESs, one based on fatty acids and the other on fatty alcohols, were prepared and applied as a microextraction solvent. The study results showed that 1-octanol/ tricaprylylmethylammonium chloride-based DES (DES-14) had the best extraction efficiency. The vortex-assisted method exhibited better extraction efficiency than the heating, ultrasound, and microwave auxiliary methods in LLME. The main factors affecting the vortex-assisted LLME were optimized statistically using the Box-Behnken design (BBD) combined with response surface methodology (RSM). The optimal conditions for LOF and COF were as follows: 14:174 μL DES, 5.7 min vortex-assisted time, and 8.7% NaCl, w/v. Under these conditions, hydrophobic DES-based LLME was established for extraction and determination LOF and COF from environmental water, and the extraction recoveries of LOF and COF exceeded 94.8%. The proposed hydrophobic DES-based LLME method provides high precision, good linearity, acceptable limit of detection (LOD) and limit of quantification (LOQ), and satisfactory recoveries for the targets. These results support the potential of this method as a new type of extraction medium to replace conventional hydrophobic organic solvents in various applications.

Quercetin is a phytochemical with disease prevention and health promotion activities that has attracted significant research attention. In this study, choline chloride and betaine-based natural deep eutectic solvents were prepared using a heating method. Their physical and chemical properties were also tested. Then, they were applied to extract quercetin from onion and broccoli with ultrasonic-assisted solid liquid method coupled with HPLC. Three factors (temperature, amount, and time) were considered for the optimization of the extraction assays. In the optimal conditions, the extraction recoveries were 88.91–98.99%, 88.45–99.01%, and 89.56–98.74% for quercetin, isorhamnetin, and kaempferol. Tailor-made natural deep eutectic solvents could be applied as sustainable and safe extraction media for biochemical applications.

Two types of molecular-imprinted polymers-based magnetic chitosan with facile deep eutectic solvent-functional monomers (Fe O -CTS@DES-MIPs) were synthesized and applied as adsorbents in magnetic solid-phase extraction (MSPE) for the selective recognition and separation of (+)-catechin, (-)-epicatechin, and (-)-epigallocatechin gallate in black tea. The obtained Fe O -CTS@DES-MIPs were characterized by Fourier transform infrared spectroscopy and field emission scanning electron microscopy. The selective recognition ability was examined by adsorption experiments. The actual amounts of (+)-catechin, (-)-epicatechin, and (-)-epigallocatechin gallate extracted from black tea using Fe O -CTS@DES-MIPs by the MSPE method were 13.10, 6.32, and 8.76 mg/g, respectively. In addition, the magnetic Fe O -CTS@DES-MIPs showed outstanding recognition and selectivity. Therefore, it can be used to separate bioactive compounds from black tea. The new-type of DES adopted as the functional monomer in this paper provides a new perspective for the recognition and separation of bioactive compounds.

Two-dimensional (2D) boron nitride (BN) were developed as a 2D scaffold material in preparation of magnetic molecularly imprinted polymers (MMIPs).

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