采用核磁共振/液相色谱-质谱异相关谱方法开展药用植物草棉活性提取物中多组分的同步结构分析研究

基于不完全分离分析策略,建立了NMR/LC-MS异相关谱(NMR/LC-MS HCS)方法对系列混合物样品的LC-MS和NMR谱数据的整合分析,发掘混合物图谱中来自同一组分的LC-MS和NMR谱数据间的内在相关性.以新疆维吾尔民族药用植物草棉(Gossypium herbaceam L.)花瓣的乙醇提取物(AB-8-2...     

Comparison of high-performance liquid chromatography — Mass spectroscopy and capillary electrophoresis— mass spectroscopy for the analysis of phenolic compounds in diethyl ether extracts of red wines

Summary Reversed-phase high-performance liquid chromatography-mass spectroscopy (HPLC-MS) and capillary electrophoresis-mass spectroscopy (CE-MS) have been compared for the analysis of phenolic compounds in diethyl ether extracts of red wines. MS was performed in the electrospray negative-ionization mode. Despite the much higher separation efficiency of CE compared with LC, LC-MS furnishes far superior information for elucidation of the structure of the constituents. LC-MS enabled the identification of twenty-four compounds whereas only thirteen were characterized by CE-MS.     

Identification and determination of the major constituents in Kai‐Xin‐San by UPLC‐Q/TOF MS and UFLC‐MS/MS method

In order to have overall chemical material information of Kai‐Xin‐San (KXS), the reliable ultra‐high‐performance liquid chromatography quadrupole time‐of‐flight mass spectrometer (UHPLC–Q‐TOF‐MS) and ultra‐fast liquid chromatography mass spectrometer (UFLC‐MS/MS) methods were developed for the identification and determination of the major constituents in KXS. Moreover, the UHPLC–Q‐TOF‐MS method was also applied to screen for multiple absorbed components in rat plasma after oral administration of KXS. The UHPLC–Q‐TOF‐MS method was achieved on Agilent 6520 Q‐TOF mass and operated in the negative ion mode. Good separation was performed on a ZORBAX Eclipse Plus C18 column with a gradient elution at a flow rate of 0.2 ml/min. A total of 92 compounds in KXS were identified or tentatively characterized based on their exact molecular weights, fragmentation patterns, and literature data. A total of 26 compounds including 23 prototype components and three metabolites were identified in rat plasma after oral administration of KXS. Then, 16 major bioactive constituents were chosen as the benchmark substances to evaluate the quality of KXS. Their quantitative analyses were performed by a triple quadrupole tandem mass spectrometer (MS/MS) operating in multiple‐reaction monitoring mode(MRM). The analysis was completed with a gradient elution at a flow rate of 0.4 ml/min within 35 min. The simple and fast method was validated and showed good linearity, precision, and recovery. Furthermore, the method was successful applied for the determination of 16 compounds in KXS. All results would provide essential data for identification and quality control of active chemical constituents in KXS. Copyright © 2016 John Wiley & Sons, Ltd.     

High throughput qualitative analysis of polyphenols in tea samples by ultra-high pressure liquid chromatography coupled to UV and mass spectrometry detectors

The analysis of polyphenols in tea extracts is important due to their potential health benefits. Therefore, efficient and high throughput analytical methods have been developed for the separation of seven predominant polyphenols, also known as catechin derivatives, present in tea extracts. Columns packed with sub-2-μm particles operating at elevated pressure (UHPLC strategy) were selected to improve chromatographic performance. The potential of UHPLC–UV was demonstrated with baseline resolution of all standard catechins in only 30 s using a 50-mm column packed with 1.7-μm particles. When dealing with real samples such as tea extracts, however, longer columns of up to 150 mm in length were employed to enhance the separation of catechin derivatives and other constituents within the tea samples while maintaining an acceptable analysis time. Two strategies based on 2-D experiments were proposed to clearly identify catechins. Firstly, a liquid–liquid extraction procedure was added prior to the UHPLC–UV analysis to decrease the complexity of the sample. Secondly, UHPLC was coupled to ESI-MS/MS to attain sufficient sensitivity and selectivity between catechin derivatives and other constituents of tea extract. These two strategies were found extremely promising as a clear discrimination of catechins from the matrix could be attained.     

Rapid and global detection and characterization of the constituents in ShengMai San by ultra-performance liquid chromatography-high-definition mass spectrometry

An ultra-performance liquid chromatography-high definition mass spectrometry (UPLC-HDMS) method was developed for detection and characterization of the chemical constituents in ShengMai San (SMS), a traditional Chinese medical formula (TCMF). The full-scan LC-MS/MS data sets combined with extra mass were acquired within 14 min using UPLC-HDMS in the MS(E) mode in a single injection. As a result, 92 compounds were identified by comparing the accurate mass and fragments information with that of the authentic standards as well as by MS analysis and the correlative references data. These constituents included ginsenosides, lignans, steroidal saponins and homoisoflavanones. Among them, 25-hydroxyginsenosides were discovered in SMS for the first time. Compare with the previous studies, our research detected more compounds and presented more rapid by applying UPLC-HDMS. It is concluded that a rapid and effective method has been established based on UPLC-HDMS with the utilization of MS(E) , which shows high sensitivity and resolution that is suitable for identifying the constituents of SMS, and this method could be applied to other TCMF.     

Rapid separation and identification of major constituents in Pseudolarix kaempferi by ultra‐performance liquid chromatography coupled with electrospray and quadrupole time‐of‐flight tandem mass spectrometry

A rapid and reliable method based on ultra‐performance liquid chromatography (UPLC) coupled with photodiode‐array detection (PDA) and electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry (ESI‐Q‐TOF‐MS/MS) has been developed for separation and identification of major constituents in extracts of root bark of Pseudolarix kaempferi Gordon (PKG). Identification of the constituents was carried out by interpretation of their retention times, UV absorption spectra, MS and MS/MS spectra, as well as the data provided by authentic standards and literatures. A total of 20 components were separated in only 8.0 min on a small particle size C₁₈ column (1.7 µm). These components included nine diterpene acids, seven glycosides and four triterpenoids, among which pseudolaric acid C‐O‐β‐D‐glucopyranoside and pseudolaric acid C₂‐O‐β‐D‐glucopyranoside were separated and identified for the first time in this study. Furthermore, the fragmentation patterns of the three types of compounds were elucidated for the first time. This established UPLC‐PDA/Q‐TOF‐MS/MS method is reliable and effective for the separation and identification of the 20 compounds and will be useful for quality control of the crude materials of Pseudolarix kaempferi Gordon and their related preparations. Copyright © 2009 John Wiley & Sons, Ltd.     

A modified method for the analysis of organics in industrial wastewater as directed by their toxicity to Vibrio fischeri

A method for the identification of toxic compounds in industrial wastewater is presented, consisting of sequential solid phase extraction (SPE), fractionation by HPLC and GC-MS for compound identification. All analytical steps are accompanied by an automated detection of the aquatic toxicity by luminescence inhibition of Vibrio fischeri, which helps to reduce the large number of samples and subsamples that have to be processed by exluding those without toxic effects. The advantages of this procedure in comparison to previous methods of toxicity directed water analysis are discussed. The procedure was successfully applied to various samples of tannery wastewater, showing that benzothiazoles account for the major toxicity of tanyard wastewater. For very polar wastewater constituents, such as in beamhouse wastewaters, the use of LC-MS/MS for the final compound identification is suggested. Received: 25 September 1998 / Revised: 20 November 1998 / Accepted: 26 November 1998     

A modified method for the analysis of organics in industrial wastewater as directed by their toxicity to Vibrio fischeri

A method for the identification of toxic compounds in industrial wastewater is presented, consisting of sequential solid phase extraction (SPE), fractionation by HPLC and GC-MS for compound identification. All analytical steps are accompanied by an automated detection of the aquatic toxicity by luminescence inhibition of Vibrio fischeri, which helps to reduce the large number of samples and subsamples that have to be processed by exluding those without toxic effects. The advantages of this procedure in comparison to previous methods of toxicity directed water analysis are discussed. The procedure was successfully applied to various samples of tannery wastewater, showing that benzothiazoles account for the major toxicity of tanyard wastewater. For very polar wastewater constituents, such as in beamhouse wastewaters, the use of LC-MS/MS for the final compound identification is suggested.     

Qualitative and quantitative analysis of the major constituents in Acorus tatarinowii Schott by HPLC/ESI‐QTOF‐MS/MS

Acorus tatarinowii Schott (ATS) is a well‐known traditional Chinese medicine (TCM) for the treatment of epilepsy, amnesia and insomnia. In this study, a methodology utilizing high‐performance liquid chromatography (HPLC) coupled with electrospray ionization quadrupole time‐of‐flight mass spectrometry (ESI‐QTOF‐MS/MS) was established for the separation and structural identification of the major chemical constituents in ATS for the first time. Overall, 46 major constituents including flavonoid glycosides, phenylpropane derivatives, amides and lignans were identified or tentatively characterized. Seven major constituents, including four phenylpropane derivatives and three lignans, were further quantified as marker substances, which showed good linearity within the test ranges. These results indicated that the developed quantitative method was linear, sensitive, and precise for quality control of ATS. Copyright © 2014 John Wiley & Sons, Ltd.     

Rapid Screening and Identification of Polar Constituents from Brazilian Arnica Lychnophora sp. by LC-UV/DAD-ESI-MS and LC-UV/DAD-ESI-MS/MS Analysis

This paper describes an analytical method for the rapid screening and identification of the phenolic constituents present in the polar extracts of different Lychnophora spp. using LC-UV/DAD-ESI-MS and LC-UV/DAD-ESI-MS/MS. Compounds were identified based on UV, retention time, MS experiments and MS/MS of precursor ion or standard. On-line phytochemical investigation of Lychnophora spp. allowed for the identification of flavonoids, chlorogenic acid derivatives and lactones. Some of the observed compounds were for the first time identified in Lychnophora species in a fast analytical procedure. The data obtained here may be helpful to the investigation of polar constituents from other Lychnophora species.     

Nuclear magnetic resonance and liquid chromatography-mass spectrometry combined with an incompleted separation strategy for identifying the natural products in crude extract

NMR and LC-MS combined with an incompleted separation strategy were proposed to the simultaneous structure identification of natural products in crude extracts, and a novel method termed as NMR/LC-MS parallel dynamic spectroscopy (NMR/LC-MS PDS) was developed to discover the intrinsic correlation between retention time (Rt), mass/charge (m/z) and chemical shift (δ) data of the same constituent from mixture spectra by the co-analysis of parallelly visualized multispectroscopic datasets from LC-MS and ¹H NMR. The extracted ion chromatogram (XIC) and ¹H NMR signals deriving from the same individual constituent were correlated through fraction ranges and intensity changing profiles in NMR/LC-MS PDS spectrum due to the signal amplitude co-variation resulted from the concentration variation of constituents in a series of incompletely separated fractions. NMR/LC-MS PDS was applied to identify 12 constituents in an active herbal extract including flavonol glycosides, which was separated into a series of fractions by flash column chromatography. The complementary spectral information of the same individual constituent in the crude extract was discovered simultaneously from mixture spectra. Especially, two groups of co-eluted isomers were identified successfully. The results demonstrated that NMR/LC-MS PDS combined with the incompleted separation strategy achieved the similar function of on-line LC-NMR-MS analysis in off-line mode and had the potential for simplifying and accelerating the analytical routes for structure identification of constituents in herbs or their active extracts.     

Qualitative analysis of chemical constituents in traditional Chinese medicine analogous formula cheng‐Qi decoctions by liquid chromatography–mass spectrometry

Cheng‐Qi decoctions (CQs), a group of analogous formulas, are well‐known traditional Chinese preparations used as purgative remedies to treat ‘internal heat’‐induced symptoms, which manifest as a bloated and painful abdomen, hard stools, fever and other clinical observations. In this study, HPLC‐ESI‐MS/MS and UPLC‐TOF‐MS were employed for separation and structural identification of constituents in CQs. As a result, a total of 90 compounds, including seven anthraquinones, 39 flavones, 21 glycosides, 11 stilbene glycosides, six organic acids, five coumarins and one lignans, were detected and tentatively identified in CQs extracts. The characterization results shed some light on the scientific foundation for clinical application of the CQ analogous formulas. Our results also indicate that the HPLC‐MS method is useful for the systemic identification of major constituents in traditional Chinese medicine formulas. Copyright © 2015 John Wiley & Sons, Ltd.     

Capillary electrophoresis/mass spectrometry: a promising tool for the control of some physiologically hazardous compounds. I-derivatives of 3-quinuclidinol

A method based on the coupling of capillary electrophoresis with mass spectrometry (CE/MS) was developed for the monitoring of 3-quinuclidinol and its four N-alkyl derivatives (methyl, ethyl, propyl and isopropyl derivatives). A fragmentation study (collision-induced dissociation of ions in an ion trap) and optimization of the ion optics set-up for CE/MS experiments using direct infusion of a methanolic solution of the standards into the mass spectrometer were carried out in advance. Molecular ions of all quaternary compounds and the quasi-molecular ion [M + H]+ of free 3-quinuclidinol prevail in the mass spectra. In the MS/MS of propyl and isopropyl derivatives, the elimination of the alkyl chain dominates, leading to the ion at m/z 128. The fragmentation of the other compounds is more complex. Previous CE separation of the mixture of isobaric propyl and isopropyl derivatives is necessary for their unambiguous identification. A 10 mM ammonium acetate buffer (pH 4.0) is the optimum running electrolyte, allowing the CE separation of methyl, ethyl, propyl and isopropyl derivatives. A 0.5% (v/v) solution of acetic acid in methanol provides sufficient detection sensitivity when used as the sheath liquid. Limits of detection of 0.1 ppm for 3-quinuclidinol and 0.05 ppm for quaternary derivatives were achieved under the optimum conditions. The optimized method was applied to the determination of 3-quinuclidinol and related quaternary derivatives spiked into a sample of pond water. The experimental set-up for CE/MS/MS was investigated, which strongly increases the identification capability of the technique.     

HPLC/QTOF‐MS/MS application to investigate phenolic constituents from Ficus pandurata H. aerial roots

Ficus pandurata H. aerial roots are used as a traditional Chinese medicine for the treatment of uarthritis, indigestion and hyperuricemia. However, the bioactive constituents responsible for the pharmacological effects of F. pandurata H. are unclear. A simple and efficient HPLC/QTOF‐MS/MS (high‐performance liquid chromatography/electrospray ionization with quadrupole time‐of‐flight tandem mass spectrometry) method was established to detect and identify active constituents in the n‐butanol extract of F. pandurata H. aerial roots. Chemical constituents were separated and investigated by HPLC/QTOF‐MS/MS in the negative‐ion mode. Thirty‐seven compounds, including hydroxycinnamic acid derivatives, hydroxybenzoic acid derivatives, hydroquinone glycosides, flavonoid glycosides, etc., were identified or tentatively characterized in the n‐butanol extract of F. pandurata H. aerial roots by comparing the UV spectra, accurate mass spectra and fragmentation pathways and retrieving the reference literatures. Moreover, the flavonoid trisaccharides and hydroxybenzoic acid derivatives were tentatively characterized in F. pandurata H. for the first time. The analytical tool used here is very valuable in the rapid separation and identification of the multiple and minor constituents in the n‐butanol extract of F. pandurata H. aerial roots. Copyright © 2014 John Wiley & Sons, Ltd.     

High throughput screening and antioxidant assay of dibenzo[a,c]cyclooctadiene lignans in modified-ultrasonic and supercritical fluid extracts of Schisandra chinensis Baill by liquid chromatography--mass spectrometry and a free radical-scavenging method

Dibenzo[a,c]cyclooctadiene lignans of Schisandra chinensis Baill are well known because of their hepatoprotective activity, antioxidant activity, and anticancer effect. For the isolation of the dibenzo[a,c]cyclooctadiene lignans of Schisandra chinensis Baill two extraction methods were used: modified-ultrasonic extraction and supercritical fluid extraction. A specific and fast analytical method for structure identification is established for quality control because structure elucidation could be accomplished by means of liquid chromatography-mass spectrometry (LC-MS) technologies. The separation and identification of the compounds were completed by: (i) a water-acetonitrile gradient system using a C18 reversed-phase column; (ii) UV detection at 225 nm; (iii) MS/MS experiments with electrospray ionization interface (ESI) ion trap mass spectrometry in the positive mode. Normalized collision energy was used to obtain fragment ions of structural relevance in the LC-MS/MS. These results provided a reliable LC-MS/MS method for the determination of the dibenzo[a,c]cyclooctadiene lignans from Schisandra chinensis Baill. Finally, we also detected 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging effects (%) of the modified-ultrasonic and supercritical fluid extracts of Schisandra chinensis Baill compared with 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox). The antioxidant activities of the modified-ultrasonic and supercritical fluid extracts were lower than that of trolox.     

Multidimensional liquid chromatography for sample characterisation

While LC finds enormously widespread use in almost all areas of chemical science, the technique is limited as a means of identification because compounds do not elute with unique retention times. This limitation spurred the growth of hyphenated instrumental methods of analysis, such as LC-MS/MS, which because of the MS/ MS detection became a method of identification. However, techniques like LC-MS/ MS are specialised and require high initial purchase and running costs, inhibiting the more widespread growth of the technique. In an attempt to increase the separation power of LC, multi-dimensional LC was developed. This expanded the separation space and subsequently has allowed the development of methods with fingerprinting ability due to the lower probability of component overlap. The work in this study illustrates the application of 2-D LC as a means of chemical fingerprinting. We employed a sample base of various low molecular weight oligostyrenes and their diastereomers that represent a population of compounds whose selectivities in a one-dimensional separation are almost unity and hence essentially impossible to separate. Yet in a 2-D domain almost all individual components occupy unique 2-D retention times.     

Large-scale muLC-MS/MS for silver- and Coomassie blue-stained polyacrylamide gels

2-DE combined with LC-MS/MS has become a routine, reliable protein separation and identification technology for proteome analysis. The demand for large-scale protein identifications after 2-DE separation requires a sensitive and high-throughput LC-MS/MS method. In this report, a simple, splitless, fully automated capillary LC-MS/MS system was described for the large-scale identification of proteins from gels stained with either silver or CBB. The gel samples were digested and peptides were extracted using an in-gel digestion workstation. The peptides were automatically introduced into a capillary column by an autosampler connected to an HPLC pump. A nanoLC pump was then used to deliver the gradient and elute the peptides from the capillary column directly into an LCQ IT mass spectrometer. Neither a peptide trapping setting nor a flow split is needed in this simple setup. The collected MS/MS spectra were then automatically searched by SEQUEST, and filtered and organized by DTASelect. Hundreds of silver-stained or CBB-stained Shewanella oneidensis, Geobacter sulfurreducens, and Geobacter metallireducens proteins separated by denaturing or nondenaturing 2-DE were digested and routinely analyzed using this fully automated muLC-MS/MS system. High peptide hits and sequence coverage were achieved for most CBB-stained gel spots. About 75% of the spots were found to contain multiple proteins. Although silver staining is not commonly thought to be optimal for MS analysis, protein identifications were successfully obtained from silver-stained 2-DE spots detected using methods with and without formaldehyde for protein fixation.     

Characterization of N-acyl-D-biotinols by particle-beam liquid chromatography-mass spectrometry. An alternative to probe mass spectrometry for thermally labile samples.

In the course of preparing biotin-labeled nucleic acid probes, it was necessary to verify structures of intermediate N-acyl derivatives of biotinol. Characterization by mass spectrometry (MS) involved use of particle-beam liquid chromatography (LC)-mass spectrometry MS to supplement standard heated-solids probe techniques. The probe data for a sample of N-toluoylbiotinol indicated it to be a mixture of mono- and di-toluoylbiotinols which was inconsistent with other analytical information. Analysis of the same sample by LC-MS on a reversed-phase column with a water-acetonitrile gradient showed a single major peak with spectrum consistent with that for the monotoluoyl species. These results suggested that a thermal transacylation reaction might be occurring in the probe during heating prior to volatilization and ionization. This was confirmed by heating the sample to 200 degrees C and then repeating the LC-MS analysis to find peaks now present for biotinol and ditoluoylbiotinol as well as the starting material. These results demonstrate the value of particle-beam LC-MS as a technique for obtaining electron-impact mass spectra of thermally sensitive compounds.     

Identification of caffeic acid derivatives in Actea racemosa (Cimicifuga racemosa,black cohosh) by liquid chromatography/tandem mass spectrometry

Caffeic acid derivatives occurring in black cohosh [Cimicifuga racemosa (L.) Nutt., Actaea racemosa (Ranunculaceae)], some of which may have pharmacological activity, were analyzed using high-performance liquid chromatography (HPLC) electrospray ionization tandem mass spectrometry (ESI-MS/MS) with the aim of developing a methodology for their rapid identification in a complex plant matrix. Based on these studies, structurally characteristic product ions and neutral molecule losses were identified, which were then used during LC/MS/MS with product ion scanning, precursor scanning and constant neutral loss scanning to detect caffeic acid derivatives in a crude extract of black cohosh. Several caffeic acid derivatives were detected, and the identification of six of them were confirmed by comparison with authentic standards including caffeic acid, ferulic acid, isoferulic acid, fukinolic acid, cimicifugic acid A, and cimicifugic acid B. Four other compounds were detected that appeared to be caffeic acid derivatives based on LC/MS/MS retention times, molecular weights, and fragmentation patterns during MS/MS. Since standards were unavailable for these four compounds, they were tentatively identified using LC/MS/MS as cimicifugic acid E, cimicifugic acid F, dehydrocimicifugic acid A, and dehydrocimicifugic acid B. Dehydrocimicifugic acid A and dehydrocimicifugic acid B have not been reported previously to be constituents of black cohosh.