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Microemulsion electrokinetic chromatography (MEEKC) is a mode of capillary electrophoresis with a wide range of applications in which microemulsion is utilized as background electrolyte to achieve the separation of analytes. Microemulsions are composed of oil droplets, aqueous buffer, surfactant, and co-surfactant. Currently, conventional organic reagents act as the most commonly used oil phase in microemulsions, which are unfriendly to the environment. Recently, deep eutectic solvent (DES) has become a new type of eco-friendly solvent due to its non-toxicity. Therefore, it is of great value to establish a new MEEKC method by replacing conventional organic reagents as the oil phase with DES. The novel DES/W MEEKC method was established for phenolic compounds in Senecio scandens samples. Single-factor experiments and response surface methodology were performed to systematically optimize the crucial parameters for the method, including the type and content of the oil phase, surfactant content, concentration of borax buffer, and pH of the background solution. Under the optimized conditions, satisfactory regression curves were established for all standard analytes with correlation coefficients ≥0.9990. The method featured high sensitivity and favorable accuracy, with the instrumental detection limit in the range of 0.22–1.04 μg/mL, and intraday and interday precision for migration time expressed as relative standard deviations of 0.18–0.82% and 1.25–2.50%, respectively. The DES/W MEEKC method was successfully applied to Senecio scandens with good recoveries of 87.72–106.99%. In conclusion, the newly established DES/W MEEKC method is highly efficient, green and environmentally friendly. DES is considered a green and efficient solvent. The DES/W MEEKC method is highly efficient and environmentally friendly. Actually, the method provides a novel and effective analytical tool for the simultaneous separation and determination of multiple phenolic compounds, especially in complex plant matrices. In the future, the DES/W MEEKC method still has the prospect of being widely used in the separation of other complex phytochemicals. [Display omitted] • Deep eutectic solvent-in-water MEEKC was established. • Deep eutectic solvent was employed as the oil phase in microemulsion system. • Single-factor experiments and response surface methodology were performed. • The method was used for the determination of phenolic compounds in complex matrices. • The method was proven to be environmentally friendly and efficient. [ABSTRACT FROM AUTHOR]

A novel organic base-assisted (OB-assisted) mechanochemical extraction (MCE) method was established for the efficient extraction of water- and fat-soluble compounds from Ophiopogon japonicus. This study investigated the influence of OB type, amount of OB, grinding time, solid-liquid ratio, vortexing time, and pH. The optimal conditions obtained from the response surface methodology are 124.16 μL of n-butylamine, a grinding time of 6.06 min, and pH of 10.59. In addition, the method showed a good linear relationship (R2 > 0.99), high accuracy (relative standard deviation > 4.44%), and an acceptable recovery rate (89.99–110.52%). The results of scanning electron microscopy suggested that mechanochemical processes may destroy the cell walls and convert the target compounds into water-soluble salt forms in the presence of added OBs. Compared with other methods, the proposed MCE does not use any organic solvent in the extraction medium and reduces the extraction time. It was successfully applied to extract flavonoids and saponins from Ophiopogon japonicus. [Display omitted] • A novel organic base-assisted mechanochemical extraction method was established. • Water is used as a solvent, and no organic solvents are used. • The method can extract hydrophobic and hydrophilic compounds at the same time. • This method can be applied to complex matrixes. • It is an efficient, green and environmentally friendly method. [ABSTRACT FROM AUTHOR]

[Display omitted] • An in-situ formation of ion pair assisted LLME method was developed. • This method was suitable for the separation of highly ionized basic compounds. • The proposed method was optimized by single-factor and multi-factor experiments. • Higher extraction efficiency, better reproducibility and environmental protection were achieved. A simple and rapid method for the determination of microsacle natural alkaloids, being based on the reaction of in-situ formation of ion pair assisted liquid–liquid microextraction (LLME) was established. Microsacle alkaloids and acid dyes formed ion pairs online, which were easily extracted by bonding reagent at an appropriate pH, so as to realize the enrichment and determination of alkaloids. The experimental parameters such as pH value, vortex time, dye types, amount of dye and solvent types were investigated and optimized. Under the optimum conditions, good linear relationships (R2 ≥ 0.9995) were obtained, the detection limits of the proposed method were between 8.9 and 16.7 ng/mL, and the average recoveries of four alkaloids ranged from 87.20 to 102.50%. These results demonstrated that the LLME procedure was a potential method for the separation and determination of alkaloids from natural medicinal materials. [ABSTRACT FROM AUTHOR]