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Introduction Erycibe obtusifolia and E. schmidtii are widely used in traditional Chinese medicine (TCM) to treat joint pain and rheumatoid arthritis. With the reduction of wild E. obtusifolia and E. schmidtii resources, Porana sinensis has been widely used as a substitute. However, few studies have been conducted on the chemical composition and quality control of P. sinensis. Objective To clarify the chemical composition and improve the quality control of P. sinensis. Methodology We developed an ultra‐high performance liquid chromatography electrospray ionisation Q‐Exactive Focus tandem mass spectrometry (UHPLC‐ESI‐Q‐Exactive Focus‐MS/MS) method to characterise the chemical constituents of P. sinensis. A strategy based on a combination of high‐performance thin‐layer chromatography (HPTLC) and direct analysis in real‐time (DART) ion source was proposed for the identification of alkaloid components in P. sinensis. Thin‐layer chromatography (TLC) autography for 2,2′‐diphenyl‐1‐picrylhydrazyl free radical (DPPH˙) and TLC bioautography for xanthine oxidase were used to rapidly screen marker compounds for high‐performance liquid chromatography (HPLC) determination of P. sinensis. Based on the selected marker compounds, a HPLC method for the quantitative determination of eight marker compounds in P. sinensis was developed. Results Eighteen compounds in P. sinensis were identified by UHPLC‐Q‐Exactive MS. Taken together with the results of TLC autography and TLC bioautography, eight compounds were chosen as marker compounds for HPLC determination of P. sinensis. The alkaloid components in P. sinensis were identified as Baogongteng A and Baogongteng C by DART‐MS. Conclusion We systematically clarified the chemical composition of P. sinensis for the first time, and potentially improved its quality control. These results should promote the application of P. sinensis as a new resource for Caulis Erycibes.

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A new Methoxy poly(ethylene glycol)-anchored polymer sensor P1, which contains anthracene fluorephore and di-2-picolylamine metal ions binding site, has been easily synthesized by "click reaction". In pure aqueous solution, P1 can coordinate with Hg 2＋ quickly to form 1∶1 stoichiometry P1-Hg 2＋ complex, with quenching the fluorescence of P1. In addition, P1-Hg 2＋ shows exclusive fluorescence turn-on sensing of cysteine (Cys) over other amino acids for the displacement method.