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The mixed enzymes-assisted mechanical bio-extraction method was first used to extract polysaccharides from Dendrobium officinale. Different parameters including the ratio of enzyme, the amount of enzyme, the grinding time, the extraction time and the solid/liquid ratio were investigated by single factor experiments and multifactorial experiments. Through the response surface methodology the optimal extraction conditions were obtained with the ratio of cellulase to pectinase was 2: 1 and total amount of enzyme was 0.23 mg, the grinding time of 11.48 min, the extraction time of 5.99 min. The obtained polysaccharide extracts were hydrolyzed and derivatized and then injected into high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF/MS) for monosaccharide composition analysis. After optimization of the chromatographic conditions (including mobile phase and column), twelve monosaccharides were successfully determined within 20 min. The proposed method provided satisfactory linearity with the correlation coefficients higher than 0.99, suitable recoveries (81.46-114.92 %), acceptable reproducibility ranging from 0.06 % to 4.77 %, low limits of detection (0.70-45.45 ng/mL). Compared with other methods, this method makes the extraction efficiency much higher and has the advantages of simple operation, environmental friendliness and mild extraction conditions. Therefore, this method can be used for the extraction of polysaccharides from plants and the determination of monosaccharides and has the potential to be used in more areas., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

An online sandwich derivatization and stacking strategy using capillary electrophoresis was developed and successfully applied to the preconcentration of multi-amino acids in two functional food samples. Amino acids were derived with 4-Chloro-7-nitro-1, 2, 3-benzoxadiazole (NBD-Cl) to make the new compounds with chromophore in the stacking process, then the derivatives were stacked by on-column sample preconcentration and detected at 475 nm UV wavelength. The novel sandwich injection sequence was amino acids, NBD-Cl, and amino acids separately. Additionally, the running buffer was 40 mM borax buffer (pH = 9.0). A succession of derivatization and stacking conditions were optimized, including buffer concentration, pressure, NBD-Cl injection time, waiting time, matrix concentration, and sample injection time. In the appropriate range, good linearity values (R 2 ) were obtained for nine amino acids at 0.996-0.999. Intra-day and inter-day precision with a relative standard deviation < 6.23 % (n = 5), the limit of detection in the range of 2.8-25.2 μM, and recovery ranging from 83.2 to 108.2 % were obtained. Besides, the enrichment factors were in range of 8-62 for nine AAs. The stacking approach was successfully applied to soybean and Dendrobium officinale samples, which shows great potential in the determination of free amino acids in samples containing complex matrices., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Dendrobium has great medicinal value, and their active components vary across different species of Dendrobium. In this study, a two-dimensional ion mobility mass spectrometry point image based on retention time and drift time was first proposed, and the collision cross-section values of Dendrobium metabolites were calculated by the IM browser, which can identify the targeted compounds more accurately, especially for isomeric compounds. During the experimental process, a total of 74 batches of Dendrobium samples containing nine species of Dendrobium were analyzed by ultrahigh-performance liquid chromatography coupled with ion mobility quadrupole-time-of-flight mass spectrometry. Nontargeted plant metabonomics combined with multivariate statistical analysis was used to realize the clustering of different species of Dendrobium , which made the identification more scientific. Therefore, this method can realize the analysis of multiple active components in Dendrobium , can be used for the identification of Dendrobium teas and can provide a reference for the quality control of Dendrobium. • Two-dimensional IM-MS point image technology was first proposed. • UHPLC-IM-Q-TOF MS was first used for the determination of plant teas. • Nontargeted metabonomics was used for the identification of Dendrobium species. [ABSTRACT FROM AUTHOR]