ABSTRACT
OBJECTIVE To establish the ion mobility mass spectrometry method for simultaneous determination of epiberberine， berberine， coptisine， palmatine， calycosin-7-glucoside， 3，5-O-dicaffeoylquinic acid， 4，5-O-dicaffeoylquinic acid and chlorogenic acid in Jinqi jiangtang tablets. METHODS Ion mobility mass spectrometry method was used. The determination was performed on Waters ACQUITY UPLC HSS T3 （2.1 mm×50 mm， 1.8 μm） with mobile phase consisted of 0.1% formic acid solution-acetonitrile （gradient elution） at the flow rate of 0.3 mL/min. The column temperature was 40 ℃， and the injection volume was 5 μL. The contents of 8 components in Jinqi jiangtang tablets were determined by scanning detection under positive and negative ion modes with an electric spray ion source， and setting ion mobility mass parameters according to the peak response of each component. RESULTS The results showed that the linear relationship of the eight components was good within their respective ranges （r≥0.999）； RSDs of precision， repeatability and stability （24 h） tests were not more than 4.0%； average recoveries were 94.6%-101.2% ， RSDs were 2.6%-3.9% （n＝9）. The contents of the above eight components in three batches of Jinqi jiangtang tablets were 3.060-3.545， 24.50-26.74， 2.795-4.149， 1.437-2.501， 0.204-0.242， 0.950-1.281， 2.272-2.828， 7.314- 7.960 mg/g， respectively. CONCLUSIONS The established method has high sensitivity and good reproducibility， and can provide reference for the quality control of the preparation.
ABSTRACT
A strategy combining collision cross section(CCS) prediction and quantitative structure-retention relationship(QSRR) model for quinoline and isoquinoline alkaloids was established based on UHPLC-IM-Q-TOF-MS and applied to Phellodendri Chinensis Cortex and Phellodendri Amurensis Cortex. The strategy included the following three steps.(1) The molecular features were extracted by the "find features" algorithm.(2) The potential quinoline and isoquinoline alkaloids were screened by filtering the original characteristic ions extracted from Phellodendri Chinensis Cortex and Phellodendri Amurensis Cortex by the established CCS vs m/z prediction interval.(3) According to the retention time of candidate compounds predicted by QSRR model, the chemical constituents were identified in combination with the characteristic fragment ions and pyrolysis law of secondary mass spectrometry. With the strategy, a total of 80 compounds were predicted, and 15 were identified accurately. The strategy is effective for the identification of small analogs of traditional Chinese medicine.
Subject(s)
Chromatography, High Pressure Liquid , Algorithms , Alkaloids , Isoquinolines , QuinolinesABSTRACT
@#Glycosylation of proteins, one of the most prevalent and complex post-translational modifications occurring in nature, plays a crucial role in regulating protein net charge, conformation, binding properties and, ultimately, biological function.Traditional structural techniques are not amenable for glycoproteins due to the inherent heterogeneity of oligosaccharides.With the advances in analytical technique, mass spectrometry displays an increasingly crucial role in elucidating the structure of glycoproteins.Mass spectrometry-based proteomic technique can dissect the chemical composition and site information of low-abundance glycosylation at the peptide level.Instead, native mass spectrometry (nMS) can analyze intact glycoproteins while maintaining the information for glycan heterogeneity, and the insights into the regulatory effects of glycosylation on protein higher order structures and interactions with other proteins or ligands.As a representative structural mass spectrometry tool, ion mobility-based nMS strategy is powered by its conformer-resolving capability and by the feasibility of conformer manipulation through collision-induced unfolding.Consequently, native IM-MS analysis can provide rich information of dynamic protein conformations, allowing for the rapid identification and differentiation of protein isoforms in an unprecedented manner.In this review, we briefly introduced two emerging native IM-MS analytical modes, dynamic conformer-resolving mode and glycoform-resolving mode.Besides, we also discussed the recent progress of conformational and topological characterization of intact glycoproteins with three typical model systems based on two above-mentioned emerging modes of native IM-MS.