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.

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.