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A novel method for biphasic extraction and separation of different polysaccharides from Radix Sophorae Tonkinensis (RST) was developed by microwave-assisted aqueous two-phase extraction (MAATPE) in a one-step procedure. Using ethanol/Na2HPO4 system as a green extractant, the effects of the composition of the aqueous two-phase system (ATPS), extraction temperature and extraction time were investigated by single-factor experiments coupled to response surface methodology (RSM) through UV–vis analysis. Under the optimum conditions, extraction yields of two polysaccharides from top and bottom phases were 8.52 ± 0.21% (w/w) and 2.18 ± 0.08% (w/w), respectively. Compared with heating solvent extraction (HSE) and ultrasonic assisted extraction (UAE), MAATPE exhibited higher extraction efficiency. By means of Fourier transform infrared spectroscopy (FT-IR) and high-performance gel permeation chromatography (HPGPC), two polysaccharides obtained from both phases had the characteristics of homogenous heteropolysaccharides, but there were some differences in chemical structures and the molecular weight from each other. Both polysaccharides could be extracted respectively from RST to the top ethanol-rich phase and the bottom salt-rich phase due to their polarity difference. Furthermore, the chemical compositions of two polysaccharides were confirmed by high-performance liquid chromatography (HPLC) analysis after hydrolysis and derivatization, the molar ratios of monosaccharides were glucose: arabinose: galactose: rhamnose: mannose: glucuronic acid: aminogalactose = 63.70: 18.21: 7.00: 5.10: 3.13: 1.78: 1.07 for the polysaccharide in the top phase and 75.24: 3.79: 3.71: 3.37: 2.51: 1.43: 9.95 for those in the bottom phase, respectively. By means of extraction process analysis and scanning electron microscopy (SEM), the exportation of MAATPE mechanism revealed that combining microwave-assisted extraction (MAE) with aqueous two-phase extraction (ATPE) not only improved the extraction yields, but also obtained at least two different polysaccharides. Under microwave field, the ATPS could make the herb cell ruptured, and multiphase mass-transfer was accelerated. The proposed method is a rapid, simple and efficient alternative to biphasic extraction of diverse polysaccharides from natural plants.

A rapid method for simultaneous extraction and separation of multiple alkaloids from Radix Sophorae Tonkinensis (RST) was developed by microwave-assisted aqueous two-phase extraction (MAATPE) using the aqueous two-phase extraction system (ATPS) of ethanol/Na2HPO4 as the extraction solvent. The effects of key factors on extraction yield were investigated by utilizing single-factor experiment coupled to response surface methodology (RSM). The regression model by RSM was significant (p

A novel method for simultaneous determination of pyrethroids residues in Litchi fruit has been developed by HPLC-UV detection using microwave-assisted extraction (MAE) coupled with ultrasonic-assisted dispersive liquid-liquid microextraction (UADLLME). Extraction conditions of MAE and UADLLME were respectively investigated by single-factor experiments and response surface methodology. Optimized experimental conditions included 310μL of chlorobenzene as extraction solvent, 1.3mL of ethanol as dispersive solvent and 3min of extraction time for UADLLME. In the case of MAE, extraction temperature of 70°C, extraction time of 4min and solvent-to-materials ratio of 40:1 were adopted. Results demonstrated that the proposed method had good performance with linearity of 0.0050-4.98mg/L, recovery of 83.3-91.5%, RSDs below 5.6% and detection limit (LOD) of 1.15-2.46μg/L for six pyrethroids, offering higher extraction efficiency and larger enrichment factor. MAE-UADLLME provided a sensitive and efficient alternative to determination of trace amounts of pesticides residues in food samples.

A novel, efficient and specific aptamer-functionalized sorbent was successfully synthesized and applied in the analysis of ultra-trace aflatoxin M1 (AFM1) and its analogues in milk. By using a gold nanoparticle-based colorimetric analysis tool, we could determine that the AFM1-aptamer (M1-aptamer) recognized and bound AFM1 to generate an aptamer-target complex. After analysis and verification, the M1-aptamer on the surface of the carboxyl microspheres were completely modified via EDC/NHs amide formation. The effects of extraction pH, extraction buffer, concentration of Mg2+ and elution solvents were investigated by single-factor experiments to determine the most suitable analysis conditions. Using these conditions, the extraction performance of the M1-aptamer-functionalized sorbent could be studied and an analytical method for AFM1 and its analogues in milk could be established. The results of adsorption equilibrium as well as adsorption selectivity experiments indicated that the M1-aptamer offered a specific adsorption site to selectively adsorb aflatoxins exhibiting a dihydrofuran oxaphthalene scaffold. The adsorption capacity of the aptamer-functionalized sorbent was 233.1 μg/g. A studied method for the determination AFM1 in milk with low matrix effect demonstrated a good linear correlation in the range of 0 to 2.0 μg/L (R2 = 0.9982) and high detection sensitivity (detection limits of 7 ng/kg in milk and 21 ng/kg in milk power). Furthermore, excellent spiked recovery and good repeatability were obtained. The method delivered specific, accurate and reproducible results for enriching and detecting ultra-trace AFM1 and its analogues in milk.

Microwave-assisted aqueous two-phase extraction (MAATPE) was applied to simultaneous extraction of diverse polysaccharides from Lentinus edodes with aqueous two-phase extraction system (ATPS) of ethanol/ammonium sulfate as the biphasic extractant. Key factors in MAATPE process were optimized by response surface methodology, and the optimum conditions were concluded as follows: the ATPS composition of ethanol concentration 26.0% (w/w) and (NH4)2SO4 concentration 19.58% (w/w), extraction temperature 78.7 °C, extraction time 19.55 min and solid-to-solvent ratio 1:50. The extraction yields of the polysaccharides from the top phase (PTP) and the bottom phase (PBP) were 2.12 ± 0.21% and 11.16 ± 0.28%, respectively. By means of FT-IR, HPGPC and HPLC analysis, PTP and PBP were different from each other in chemical structure, their average molecular weight (MW) were respectively 119,533 Da and 3906 Da. Also, the mechanism of MAATPE process was explored by composition analysis and scanning electron microscopy. Both polysaccharides exhibited stronger antioxidant activities, EC50 values of scavenging DPPH, hydroxyl and superoxide radicals for PBP achieved 580 ± 3, 83.1 ± 3.6 and 91.1 ± 0.5 μg/mL as against 560 ± 4, 76.3 ± 2.2 and 89.3 ± 2.4 μg/mL of PTP, respectively. Compared with conventional methods using a mono-phase solvent, MAATPE can not only greatly improve extraction efficiency, but also selectively extract diverse polysaccharides.