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pH-Zone refining counter-current chromatography was successfully applied to the preparative isolation and purification of six alkaloids from the ethanol extracts of Uncaria macrophylla Wall. Because of the low content of alkaloids (about 0.2%, w/w) in U. macrophylla Wall, the target compounds were enriched by pH-zone refining counter-current chromatography using a two-phase solvent system composed of petroleum ether-ethyl acetate-isopropanol-water (2:6:3:9, v/v), adding 10 mM triethylamine in organic stationary phase and 5 mM hydrochloric acid in aqueous mobile phase. Then pH-zone refining counter-current chromatography using the other two-phase solvent system was used for final purification. Six target compounds were finally isolated and purified by following two-phase solvent system composed of methyl tert-butyl ether (MTBE)-acetonitrile-water (4:0.5:5, v/v), adding triethylamine (TEA) (10 mM) to the organic phase and HCl (5 mM) to aqueous mobile phase. The separation of 2.8 g enriched total alkaloids yielded 36 mg hirsutine, 48 mg hirsuteine, 82 mg uncarine C, 73 mg uncarine E, 163 mg rhynchophylline, and 149 mg corynoxeine, all with purities above 96% as verified by HPLC Their structures were identified by electrospray ionization-mass spectrometry (ESI-MS) and 1 H-NMR spectroscopy.

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A cobalt metal-organic framework (Co MOF)-ionic liquid (IL) nanocomposite comprising the base matrix of the electrode was developed with electropolymerized molecularly imprinted polymer consisting of o-phenylenediamine (oPD) to detect carcinoembryonic antigen (CEA), a biomarker of breast cancer. First, Co MOF was synthesized using hydrothermal synthesis, which was used as an electrically conductive skeleton and functionalized with an IL. Then, CEA was employed as a template in the electropolymerization of oPD-imprinted films on the surface of screen-printed carbon electrode. Finally, the template protein was removed to form a molecularly imprinted film capable of qualitatively and quantitatively signaling CEA. Under optimized conditions, the sensor for CEA exhibits a wide detection range of 1.0×10-4-10 ng·mL-1 (0.32 V vs. Ag/AgCl) with a limit of detection and limit of quantification of 0.024 pg·mL-1 and 0.082 pg·mL-1, respectively. Besides, other parameters including the selectivity, reproducibility (RSD 2.2%), and recovery rate (92.16-103.35%) are all satisfactory. The proposed strategy provides a new route for the development of rapid breast cancer diagnostic tools.

Herein, we describe a new chiral amorphous metal–organic polyhedra used as the stationary phase for high‐resolution gas chromatography (GC). The chiral stationary phase was coated onto a capillary column via a dynamic coating process and investigated for a variety of compounds. The experimental results showed that the chiral stationary phase exhibits good selectivity for linear alkanes, linear alcohols, polycyclic aromatic hydrocarbons, isomers, and chiral compounds. In addition, the column has the advantages of high column efficiency and short analysis time. The present work indicated that amorphous metal–organic polyhedra have great potential for application as a new type of stationary phase for GC.