In the past decade, relative proteomic quantification using isobaric labeling technology has developed into a key tool for comparing the expression of proteins in biological samples. Although its multiplexing capacity and flexibility make this a valuable technology for addressing various biological questions, its quantitative accuracy and precision still pose significant challenges to the reliability of its quantification results. Here, we give a detailed overview of the different kinds of isobaric mass tags and the advantages and disadvantages of the isobaric labeling method. We also discuss which precautions should be taken at each step of the isobaric labeling workflow, to obtain reliable quantification results in large-scale quantitative proteomics experiments. In the last section, we discuss the broad applications of the isobaric labeling technology in biological and clinical studies, with an emphasis on thermal proteome profiling and proteogenomics.
Proteome/metabolism* ; Proteomics/methods* ; Reproducibility of Results ; Tandem Mass Spectrometry/methods*

From the perspective of technical evaluation, this study reviewed the current situation of application and clinical application of medical device products were detected by liquid chromatography-tandem mass spectrometry in the market in recent years. The regulatory requirements of these products in China, USA, EU and Japan were compared and analyzed, and the monitoring situation of adverse events after listing, the standards for reference and the domestic and foreign regulatory documents were combined, the clinical application and regulatory risks of the product were analyzed. The problems such as pre-treatment, system matching, adequacy of performance index requirements, inter-room consistency, reference interval and registration unit were discussed and suggestions for supervision were given, with a view to the field of product R&D and production, review and approval of supervision to provide technical reference.
Chromatography, Liquid/methods* ; Tandem Mass Spectrometry/methods* ; Reference Standards ; Japan

An HPLC-DAD-MS/MS method was developed for rapid analysis and identification of degradation products of buagafuran. Buagafuran and degradation products were separated on a Zorbax C8 column (5 microm, 4.6 mm x 150 mm) using acetonitrile-water (78 : 22) as mobile phase. The elutes were detected with diode array detector and tandem mass spectrometer via electrospray ionization source in positive ion mode. According to analysis of the retention time, UV spectra and MS, MS/MS data, combined with the possible degradation reaction of buagafuran, the structures of main degradation products were inferred. The results showed that six main degradation products were oxidation or peroxidation productions of buagafuran. Degradation product A was a double bond epoxidation product of buagafuran, degradation products B, C, D and E were the further oxidation products of degradation product A, degradation product F was a peroxidation product of buagafuran. The results indicated that the established method was effective in the rapid identification of the degradation products of buagafuran.
Chromatography, High Pressure Liquid ; methods ; Sesquiterpenes ; chemistry ; Spectrometry, Mass, Electrospray Ionization ; methods ; Tandem Mass Spectrometry ; methods

OBJECTIVETo investigate the monoterpene glycosides in Paeonia lactflora by UPLC-MS/MS.

METHODAn Acquity UPLC BEH C18 column (2.1 mm x 50 mm) with 1.7 microm particle size was used. The mobile phase was composed of acetonitrile and 0.1% formic acid in gradient mode. The flow rate was 0.4 mL x min and the chromatographic run time was 9 min for one run. The mass spectrometer equipped with an eletrospray ion source in negative ion mode.

RESULTSTotally six glycosides were analyzed and identified by the established UPLC-MS/MS method.

CONCLUSIONThe method was rapid, sensitive, and extremely useful for rapid identification of glycosides in P. lactiflora.

A quick HPLC-ESI-MS/MS method was established for simultaneous determination of three chemical compositions in Usnea, including usnic acid, diffractaic acid, and ramalic acid. The separation was performed on a chromatographic column of Agilent ZORBAX SB-C, (4.6 mm x 250 mm, 5 µm), and the mobile phase was methanol (0.05% formic acid)-0.05% formic acid solution (4 mmol ammonium acetate), with an isocratic elution at a flow rate of 0.8 ml · min⁻¹. Multiple reaction monitoring scanning mode (MRM) was performed combined with the ion switching technology in positive and negative ion switching mode to apply for the quantitative determination. The calibration curves for the above three compounds were linear in corresponding injection amount. Their average recoveries were 95.0%-105.1%, with RSDs of 1.1%-5.2%. The method was simple, rapid, accurate with high repeatability, which could provide a reference for overcalling evaluation the quality of Usnea.
Chromatography, High Pressure Liquid ; methods ; Hydroxybenzoates ; analysis ; Spectrometry, Mass, Electrospray Ionization ; methods ; Tandem Mass Spectrometry ; methods ; Usnea ; chemistry

A rapid ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometric (UPLC-ESI-MS/MS) method is developed for the qualitative identification of constituents in the flower buds of seven Lonicera species. The optimal condition of separation and detection were achieved on an AcQuity UPLC BEH C18 column with a gradient elution with acetonitrile and 0.1% acetic acid within 17 min. Among the 33 constituents detected, 6 caffeoylquinic acids (including caffeic acid), 8 flavonoids and 8 iridoid glycosides were characterized based on their fragmentation patterns in collision-induced dissociation (CID) experiments and/or by comparison with standard compounds. In addition, to statistically establish the correlation and discrimination of the Lonicera species, principle component analysis (PCA) was applied in this study. Lonicera samples were divided into well-defined groups directly related to their species based on PCA in terms of the log transformed relative contents of the major caffeoylquinic acids (including caffeic acid) as the variables. All of results indicated that the method presented here is able to classify the sample species and to reveal characteristic details of the chemical constituents of different Lonicera species.
Chromatography, Liquid ; methods ; Flowers ; chemistry ; Lonicera ; chemistry ; classification ; Principal Component Analysis ; Spectrometry, Mass, Electrospray Ionization ; methods ; Tandem Mass Spectrometry ; methods

The ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS~E) technology was employed to compare the chemical components between the aerial and underground parts of Coptis chinensis samples from different batches. According to the retention time, molecular ion peak, and LC-MS~E fragment information of the reference substances and available literature, we identified a total of 40 components. Thirty-three and 31 compounds were respectively identified in the underground part(taproots) and the aerial part(stems and leaves) of C. chinensis. Among them, 24 compounds, including alkaloids(e.g., berberine and jatrorrhizine) and phenolic acids(e.g., chlorogenic acid, quinic acid, and tanshinol), were common in the two parts. In addition, differential components were also identified, such as magnoline glucoside in the underground part and(±) lariciresionol-4-β-D-glucopyranoside in the aerial part. The analysis of fragmentation pathways based on spectra of reference substances indicated the differences among samples of different batches. Furthermore, we performed the principal component analysis(PCA) for the peak areas of C. chinensis in different batches. The results showed that the underground part and the aerial part were clearly clustered into two groups, indicating that the chemical components contained in the two parts were different. Furthermore, the results of partial least squares discriminant analysis(PLS-DA) identified 31 differential compounds(VIP value>1) between the underground part and the aerial part, mainly including alkaloids, phenolic acids, lignans, and flavonoids. This study proves that C. chinensis possesses great development potential with multiple available compounds in stems and leaves. Moreover, it sheds light on for the development and utilization of non-medicinal organs of C. chinensis and other Chinese medicinal herbs.
Chromatography, High Pressure Liquid/methods* ; Coptis chinensis ; Spectrometry, Mass, Electrospray Ionization/methods* ; Tandem Mass Spectrometry/methods* ; Technology

To characterize and identify multiple constituents in Danhong injection (DHI), a fast ultra-high performance liquid chromatography coupled to electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC-ESI-QTOF/MS) method was established and validated in the present study. A total of 63 compounds, including 33 phenolic acids, 2 C-glycosyl quinochalcones, 6 flavonoid O-glycosides, 4 iridoid glycosides, 6 organic acids, 5 amino acids, and 3 nucleosides, were identified or tentatively characterized. In conclusion, the UHPLC-ESI-QTOF/MS method is useful and efficient for in-depth structural elucidation of chemical compounds in complex matrices of herbal medicines such as DHI.
Chromatography, High Pressure Liquid ; methods ; Drugs, Chinese Herbal ; chemistry ; isolation & purification ; Spectrometry, Mass, Electrospray Ionization ; methods ; Tandem Mass Spectrometry ; methods

A liquid chromatography coupled with diode array detector (DAD) and electrospray ionization time-of-flight mass spectrometry (ESI-TOF/MS) method was developed for the screening and identification of the multiple components in Tanreqing injection, a well-known Chinese medicine injection in China. By combining the DAD spectrum and the accurate mass measurement of ESI-TOF/MS, twelve components in Tanreqing injection were identified. This study contributes to clarifying the nature of Tanreqing injection, and provides an effective and reliable process for the comprehensive and systematic characterization of complex traditional Chinese medicine preparations.
Chromatography, High Pressure Liquid ; methods ; Drugs, Chinese Herbal ; chemistry ; Molecular Structure ; Spectrometry, Mass, Electrospray Ionization ; methods ; Tandem Mass Spectrometry ; methods

OBJECTIVES: To establish an analytical method of the endosulfan concentrations （α-endosulfan and β-endosulfan） in biological samples by GC-MS/MS. To observe the distribution of endosulfan in aquatic animals and provide experimental evidence for forensic identification of relevant cases. METHODS: Acetonitrile was added to the blood and muscle samples for precipitating the protein. The endosulfan concentrations were determined by GC-MS/MS in multiple reaction monitoring mode. Qualitative analysis was performed according to the retention time and ion rate, and quantitative analysis was performed by external standard working curve method. RESULTS: In blood samples, the calibration curves of α-endosulfan and β-endosulfan ranging from 0.062 5 to 10 μg/mL had good linear relationship, the correlation coefficients （r） of which were >0.99. The limits of detection （LOD） were 1 ng/mL and 2 ng/mL and the limits of quantification （LOQ） were 4 ng/mL and 8 ng/mL, respectively. In muscle samples, the calibration curves of α-endosulfan and β-endosulfan ranging from 0.062 5 to 10 μg/g, the r of which were >0.98. The LOD were 1 ng/g and 4 ng/g and the LOQ were 4 ng/g and 16 ng/g, respectively. The accuracy of α-endosulfan and β-endosulfan was 90.76%-108.91% both in blood and muscle samples, the interday and intraday precision were 2.35%-8.71% and 5.44%-10.29%, respectively. In poisoning cases, endosulfan were detected in all parts of fish and crab and the content difference was statistically significant. CONCLUSIONS The endosulfan detection method based on GC-MS/MS established in the present study is rapid, sensitive and accurate, which can be applied to the endosulfan detection in traces biological samples. The distribution of endosulfan in fish and crab was different, which can provide evidence to the sample collection and analysis for toxicological analysis in relevant forensic identification.
Animals ; Chromatography, Gas/methods* ; Endosulfan/metabolism* ; Gas Chromatography-Mass Spectrometry/methods* ; Humans ; Limit of Detection ; Reproducibility of Results ; Tandem Mass Spectrometry/methods*