Solubility Measurement and Correlation of Itraconazole Hydroxy Isobutyltriazolone in Four Kinds of Binary Solvent Mixtures with Temperature from 283.15 to 323.15 K.

The solubility of itraconazole hydroxy isobutyltriazolone (IHI) in four commonly used binary solvent mixtures of N,N-dimethylformamide (DMF) + water, DMF + ethanol, tetrahydrofuran (THF) + water, and THF + ethanol was determined with gravimetric method at temperatures ranging from 283.15 to 323.15 K under atmospheric pressure. The solubility of IHI in all selected solvents increases with the increase of temperature. The maximum solubility of IHI exists in the solvent of DMF + ethanol (0.06523 mol·mol-1, x20 = 0.7, T = 323.15 K), while the minimum solubility exists in DMF + water (0.0003723 mol·mol-1, x20 = 0.3, T = 283.15 K). There is a co-solvency phenomenon in the mixed solvents of DMF+ ethanol, THF + water, and THF + ethanol. Four thermodynamic models, including the modified Apelblat model, the Yaws model, the Sun model, and the modified Jouyban-Acree model, were selected to fit the solubility data of IHI. All the RAD values are less than 0.0484, and RMSD values are not more than 0.001319. The Yaws model and the modified Apelblat model fit the solubility data of IHI better than the other two models. All the selected four models can fit the solubility data of IHI well.

Separation and purification of alkaloids and phenolic acids from Phellodendron chinense by pH-zone refining and online-storage inner-recycling counter-current chromatography.

In this work, eight compounds from Phellodendron chinense were separated and purified by pH-zone refining counter-current chromatography and traditional counter-current chromatography coupled with online-storage inner-recycling counter-current chromatography (IRCCC). The pH-zone-refining mode was adopted for separating 2.0 g of crude extract with the solvent system of chloroform-methanol-water (4:3:3, v/v), in which 10 mM hydrochloric acid and 10 mM triethylamine were added in the stationary and mobile phases, respectively. Meanwhile, traditional counter-current chromatography coupled with online-storage IRCCC separation was performed by the solvent system of n-hexane-ethyl acetate-methanol-water (5:5:2:8, v/v). Finally, eight compounds, including six alkaloids as 6-methylpiperidin-2-one(1), isoplatydesmine(4), berlambine(5), epiberberine(6), palmatine(7), berberine(8) and two phenolic acids as ferulic acid(2), isoferulic acid(3), were successfully obtained using these three different CCC modes with the purities over 95.0%.

Preparation of a pyridyl covalent organic framework via Heck cross-coupling for solid-phase microextraction of perfluoropolyether carboxylic acids in food.

The growing detection of emerging perfluoropolyether carboxylic acids (PFECAs) in food has raised considerable concerns about their high persistence, bioaccumulation, and toxicity. In this study, a pyridine-functionalized covalent organic framework (Py-COF) was synthesized by introducing basic pyridyl groups into Br-COF via Heck cross-coupling. According to density functional theory, PFECAs were adsorbed in the pore sites of Py-COF via O-···HN+ interaction, which was the stable and predominant adsorption configuration. After systematic characterization, Py-COF was used as the coating for solid-phase microextraction combined with high-performance liquid chromatography-tandem mass spectrometry (SPME-HPLC-MS/MS) for the efficient determination of PFECAs in food. Under the optimum conditions, the method showed satisfactory linearity (R2 ≥ 0.998), low limits of detection (0.001-0.004 ng g-1), and good relative recoveries (82.5 %-112 %). The established method was satisfactorily used for the analysis of trace PFECAs in food samples.