Hydrophobic deep eutectic solvent-based ultrasonic-assisted liquid-liquid microextraction combined with GC for eugenol, isoeugenol, and methyl isoeugenol determination in aquatic products

The use of deep eutectic solvents (DESs) has great prospects because of the green and efficient characteristics, which can be used for developing analytical methods for foods. In this research, assisted by ultrasonic waves, a liquid-liquid microextraction detection method combined with gas chromatography was established for three anaesthetics (eugenol, isoeugenol, and methyl isoeugenol) in aquatic food. The processing conditions including the components, ratio of hydrogen bond acceptor and hydrogen bond donor, DES volume, ultrasonic time, and pH were evaluated and optimised to improve the extraction efficiency, which was based on the DES structures and properties. In-house method validation was carried out by applying to real samples. A Thymol: levulinic acid DES (with a molar ratio of 1:2) was used as the extractant and the recoveries were as high as 93-101% for eugenol, 90-100% for methyl isoeugenol, and 86-94% for isoeugenol with RSDs <5% under optimum conditions. The limit of detection and quantification of the eugenol compounds were 0.08-0.10 μg/mL and 0.26-0.33 μg/mL, respectively. The method has green credentials and comparable LOD to homologous apparatus, which can be used for the determination of eugenol components in aquatic food.

Optimization of Deep Eutectic Solvents Extraction of Effective Components from Phellodendron chinense Schneid by Response Surface Methodology

Taking Phellodendron chinense Schneid (PcS) as the raw material with ultrasonic-assisted eutectic solvent, the effects of various DESs on the extractable content of palmatine and berberine in PcS were investigated. On the basis of the single-factor test, the best DES was determined to be choline chloride and 1,3-propanediol (mole ratio 1 : 2). After optimizing by the response surface method, the optimum extraction conditions were as follows: the solid-liquid ratio was 1 : 30 (w/v), water content was 30% (v/v), vortex time was 7 min, ultrasonic time was 20 min, ultrasonic temperature was 60°C, ultrasonic power was 400 W, and the content of palmatine in PcS was 5.421 ± 0.283 mg/g, and the content of berberine in PcS was 15.573 ± 0.539 mg/g. Therefore, DES prepared from choline chloride and 1,3-propanediol can be used to extract palmatine and berberine from PcS. The optimized process conditions determined by the response surface method are reliable and can provide a reference for the green extraction of effective components from PcS.