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During the analysis of benziamidazole-class irreversible proton pump inhibitors,an unusual mass spectral response with the mass-to-charge ratio at[M+10]+intrigued us,as it couldn't be assigned to any literature known relevant structure,intermediate or adduct ion.Moreover,this mysterious mass pattern of[M+10]+has been gradually observed by series of marketed proton pump inhibitors,viz.omeprazole,pantoprazole,lansoprazole and rabeprazole.All the previous attempts to isolate the corresponding component were unsuccessful.The investigation of present work addresses this kind of signal to a pyridinium thiocyanate mass spectral intermediate(10),which is the common fragment ion of series of labile aggregates.The origin of such aggregates can be traced to the reactive intermediates formed by acid-promoted degradation.These reactive intermediates tend to react with each other and give raise series of complicated aggregates systematically in a water/acetonitrile solution by electrospray ioniza-tion.The structure of the corresponding pyridinium thiocyanate species of omeprazole(10a)has been eventually characterized with the help of synthetic specimen(10a').Our structural proposal as well as its origin was supported by in situ nuclear magnetic resonance,chemical derivatization and colorimetric experiments.
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The rapid and accurate authentication of traditional Chinese medicines(TCMs)has always been a key scientific and technical problem in the field of pharmaceutical analysis.Herein,a novel heating online extraction electrospray ionization mass spectrometry(H-oEESI-MS)was developed for the rapid and direct analysis of extremely complex substances without the requirement for any sample pretreatment or pre-separation steps.The overall molecular profile and fragment structure features of various herbal medicines could be completely captured within 10-15 s,with minimal sample(＜0.5 mg)and solvent consumption(＜20 μL for one sample).Furthermore,a rapid differentiation and authentication strategy for TCMs based on H-oEESI-MS was proposed,including metabolic profile characterization,characteristic marker screening and identification,and multivariate statistical analysis model validation.In an analysis of 52 batches of seven types of Aconitum medicinal materials,20 and 21 key compounds were screened out as the characteristic markers of raw and processed Aconitum herbal medicines,respectively,and the possible structures of all the characteristic markers were comprehensively identified based on Com-pound Discoverer databases.Finally,multivariate statistical analysis showed that all the different types of herbal medicines were well differentiated and identified(R2X＞0.87,R2Y＞0.91,and Q2＞0.72),which further verified the feasibility and reliability of this comprehensive strategy for the rapid authentication of different TCMs based on H-oEESI-MS.In summary,this rapid authentication strategy realized the ultra-high-throughput,low-cost,and standardized detection of various complex TCMs for the first time,thereby demonstrating wide applicability and value for the development of quality standards for TCMs.
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The direct coupling of solid-phase microextraction(SPME)to mass spectrometry(MS)(SPME-MS)has proven to be an effective method for the fast screening and quantitative analysis of compounds in complex matrices such as blood and plasma.In recent years,our lab has developed three novel SPME-MS techniques:SPME-microfluidic open interface-MS(SPME-MOI-MS),coated blade spray-MS(CBS-MS),and SPME-probe electrospray ionization-MS(SPME-PESI-MS).The fast and high-throughput nature of these SPME-MS technologies makes them attractive options for point-of-care analysis and anti-doping testing.However,all these three techniques utilize different SPME geometries and were tested with different MS instruments.Lack of comparative data makes it difficult to determine which of these methodologies is the best option for any given application.This work fills this gap by making a comprehensive comparison of these three technologies with different SPME devices including SPME fibers,CBS blades,and SPME-PESI probes and SPME-liquid chromatography-MS(SPME-LC-MS)for the analysis of drugs of abuse using the same MS instrument.Furthermore,for the first time,we developed different desorption chambers for MOI-MS for coupling with SPME fibers,CBS blades,and SPME-PESI probes,thus illustrating the universality of this approach.In total,eight analytical methods were developed,with the experimental data showing that all the SPME-based methods provided good analytical performance with R2 of linearities larger than 0.9925,accuracies between 81％and 118％,and good precision with an RSD％≤13％.
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Complicated chemical reactions occur in the decoction of traditional Chinese medicines(TCMs) which features complex components, influencing the safety, efficacy, and quality controllability of TCMs. Therefore, it is particularly important to clarify the chemical reaction mechanism of TCMs in the decoction. This study summarized eight typical chemical reactions in the decoction of TCMs, such as substitution reaction, redox reaction, isomerization/stereoselective reaction, complexation, and supramolecular reaction. With the "toxicity attenuation and efficiency enhancement" of aconitines and other examples, this study reviewed the reactions in decoction of TCMs, which was expected to clarify the variation mechanisms of key chemical components in this process and to help guide medicine preparation and safe and rational use of medicine in clinical settings. The current main research methods for chemical reaction mechanisms of decoction of TCMs were also summed up and compared. The novel real-time analysis device of decoction system for TCMs was found to be efficient and simple without the pre-treatment of samples. This device provides a promising solution, which has great potential in quantity evaluation and control of TCMs. Moreover, it is expected to become a foundational and exemplary research tool, which can advance the research in this field.
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Medicina , Medicina Tradicional China , Proyectos de InvestigaciónRESUMEN
The solid-phase microextraction technique quantifies analytes without considerably affecting the sample composition.Herein,a proof-of-concept study was conducted to demonstrate the use of coated probe electrospray ionization(coated-PESI)and coated blade spray(CBS)as ambient mass spectrometry ap-proaches for monitoring drug biotransformation.The ability of these methods was investigated for monitoring the dephosphorylation of a prodrug,combretastatin A4 phosphate(CA4P),into its active form,combretastatin A4(CA4),in a cell culture medium supplemented with fetal bovine serum.The CBS spot analysis was modified to achieve the same extraction efficiency as protein precipitation and ob-tained results in 7 min.Because coated-PESI performs extraction without consuming any samples,it is the preferred technique in the case of a limited sample volume.Although coated-PESI only extracts small quantities of analytes,it uses the desorption solvent volume of 5-10 pL,resulting in high sensitivity,thus allowing the detection of compounds after only 1 min of extraction.The biotransformation of CA4P into CA4 via phosphatases occurs within the simple matrix,and the proposed sample preparation techniques are suitable for monitoring the biotransformation.
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Probe electrospray ionization (PESI) is one of the typical types of ambient ionization technology, but its application in quantitative analysis is limited due to its poor sampling stability. Previously, we developed a new micro-pen electrospray ionization tandem mass spectrometry (μPen-ESI-MS/MS) method based on PESI. In this study, a μPen-ESI-MS/MS method to measure testosterone and dextromethorphan in liver microsome samples was developed and validated to further applicate in evaluating drug metabolism stability and CYP450 enzyme activity. A μPen-ESI-MS/MS method for detecting the CYP3A4 substrate testosterone and CYP2D6 substrate dextromethorphan in the liver microsome incubation system were developed, and the linearity, precision and accuracy of the method was validated. The validated method was further used to detect the metabolic stability of testosterone in the liver microsome incubation system. The results showed that the μPen-ESI-MS/MS had high efficiency with 0.3 min spraying time of each sample. The standard curve of the testosterone and dextromethorphan has good linearity (R2 > 0.99), the intra- and inter-batch accuracy of testosterone and dextromethorphan was 95.9%-109.3% and 90.5%-107.3%, respectively; the intra- and inter-batch precision was acceptable with RSD values of 2.4%-13.5% and 3.4%-12.1%. The half-lives of testosterone and dextromethorphan in the liver microsome incubation system were 12 min and 14 min, respectively. This study provided a rapid and sensitive μPen-ESI-MS/MS method for the assay of testosterone and dextromethorphan in liver microsome samples, and provided a new strategy for the evaluation of drug metabolism stability and CYP3A4/CYP2D6 activity.
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Desorption electrospray ionization mass spectrometry (DESI-MS) is a newly emerging in-situ ionization mass spectrometry analysis technology. The ionization process occurs in an open ambient environment at atmospheric pressure, and has the characteristics of simple sample pretreatment, quick and sensitive analysis, and is widely used in biomedicine, pharmaceutical analysis, food safety, environmental monitoring, and material characterization. Natural medicines, such as Chinese herbal medicines, contain a variety of chemical components. Extraction, separation, identification, and in vitro and in vivo efficacy evaluation of natural medicines, especially research on active ingredients with significant efficacy, have received long-term attention. The development of DESI-MS technology provides many new opportunities for direct and rapid analysis of active ingredients in natural medicines. This article briefly introduces the principles, characteristics, influencing factors, and technical progress of DESI-MS technology, and systematically summarizes progress in the research and application of this technology to natural medicines such as Chinese herbal medicines and other plant samples with pharmacological activity. The future application prospects in this field are further presented.
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Objective:To analyze and identify the flavonoids of Citri Reticulatae Pericarpium with different aging time by an ultra-performance liquid chromatography-quadrupole-electrostatic field orbitrap high resolution mass spectrometry （UPLC-Q-Orbitrap HRMS）. Method:Compounds were separated on Agilent Extend-C<sub>18</sub> column （3.0 mm×100 mm， 1.8 μm）， mobile phase was 0.1% acetic acid aqueous solution （A）-0.1% acetic acid methanol solution （B） for gradient elution （0-25 min， 5%-95%B； 25-30 min， 95%B； 30-30.1 min， 95%-5%B； 30.1-35 min， 5%B）， the flow rate was 0.4 mL·min<sup>-1</sup>， and the column temperature was set at 30 ℃. High resolution mass spectrometry was performed with electrospray ionization （ESI）， and scanned in positive and negative ion modes by means of full scan/data dependent secondary scan （Full MS/dd-MS<sup>2</sup>）. The multistage ion fragment information combined with mzCloud network database， local high resolution mass spectrometry database of traditional Chinese medicine components （OTCML）， literature information and relevant reference materials were used for accurate qualitative analysis. Result:Totally 43 flavonoids in Citri Reticulatae Pericarpium were identified， including 24 flavones， 5 flavonols， 13 dihydroflavones and 1 chalcone. The flavonoids in samples with different aging time were basically consistent in material types， but the peak area was different. According to the comparison of relative content in the peak area， it was found that the relative contents of 30 flavonoids showed an overall increasing trend with the increase of aging time. Among them， the relative contents of 24 flavonoids （such as hesperidin， diosmin， 6-demethoxytangeretin， nobiletin and tangeretin） increased significantly. There was no significant change in the relative contents of the other 13 flavonoids （such as naringenin and neohesperidin）. Conclusion:An efficient method is established in this paper to identify flavonoids in Citri Reticulatae Pericarpium with different aging time and their relative content changes rapidly and accurately. The findings provide a methodological reference for the study on pharmacodynamic material base and quality control of Citri Reticulatae Pericarpium， and it provides experimental basis that drugs processed long time ago have better effect of Citri Reticulatae Pericarpium.
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This study focused, for the first time, on the effect of ultrasonic features on the extraction efficiency of secondary metabolites in mustard seed cake (MSC). The nematostatic potential of sonicated seed cake was examined against the second-stage juveniles (J2s) of root-knot nematode,
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Detailed knowledge on tissue-specific metabolic reprogramming in diabetic nephropathy (DN) is vital for more accurate understanding the molecular pathological signature and developing novel therapeutic strategies. In the present study, a spatial-resolved metabolomics approach based on air flow-assisted desorption electrospray ionization (AFADESI) and matrix-assisted laser desorption ionization (MALDI) integrated mass spectrometry imaging (MSI) was proposed to investigate tissue-specific metabolic alterations in the kidneys of high-fat diet-fed and streptozotocin (STZ)-treated DN rats and the therapeutic effect of astragaloside IV, a potential anti-diabetic drug, against DN. As a result, a wide range of functional metabolites including sugars, amino acids, nucleotides and their derivatives, fatty acids, phospholipids, sphingolipids, glycerides, carnitine and its derivatives, vitamins, peptides, and metal ions associated with DN were identified and their unique distribution patterns in the rat kidney were visualized with high chemical specificity and high spatial resolution. These region-specific metabolic disturbances were ameliorated by repeated oral administration of astragaloside IV (100 mg/kg) for 12 weeks. This study provided more comprehensive and detailed information about the tissue-specific metabolic reprogramming and molecular pathological signature in the kidney of diabetic rats. These findings highlighted the promising potential of AFADESI and MALDI integrated MSI based metabolomics approach for application in metabolic kidney diseases.
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This paper investigated the effects of regular aerobic exercise on protein oxidative stress and apoptosis in aging rat striatum, and further analyzed its target proteins and mechanism based on differential carbonylation proteomics. Totally 24 specific pathogen-free (SPF) 23-month-old male Sprague-Dawley (SD) rats were randomly divided into aged sedentary control group (Con-SED, n = 12) and aged regular aerobic exercise runner group (Aero-EXE, n = 12). The medium intensity of regular aerobic exercise model: The intensity of maximum oxygen consumption (VO
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Objective: Using ultra-high performance liquid chromatography with diode array detection (UHPLC-DAD) and desorption electrospray ionization-mass spectrometry imaging (DESI-MSI) to analyze 15 batches of Shaoyao Gancao Decoction (SGD) substance benchmark and lyophilized powder in order to investigate the advantages of DESI-MSI in quality control of famous classical formulas. Methods: Taking SGD as the research model, fingerprints of the substance benchmark were established by UHPLC-DAD, and the content of index components (paeoniflorin, liquiritin, glycyrrhizic acid) and the yield of dry extract were also investigated. Meanwhile, as the research carrier, the lyophilized powder corresponding to SGD was dissolved in methanol and dotted on qualitative filter paper with quantitative capillary, and fixed it on the slide to make samples. The samples were analyzed on a DESI-MSI system in positive and negative ion mode with methanol-formic acid (1 000:1, flow rate of 3 μL/min) as spray solvent, N2 as spray gas (pressure of 0.5 MPa). The scanning range was m/z 100-1 200, the spatial resolution was 300 μm, the ion source temperature was 120 ℃. Results: DESI-MSI can detect not only the index components of paeoniflorin, liquiritin, glycyrrhizic acid, but also the common peaks of albiflorin. At the same time, DESI-MSI could detect 11 other components from Glycyrrhizae Radix et Rhizoma and Paeoniae Radix Alba, such as licoricesaponin G2, licoricesaponin J2, gallic acid, citric acid, p-hydroxybenzoic acid, and present their relative content visually. The qualitative analysis ability of DESI-MSI was much better than UHPLC-DAD. Conclusion: DESI-MSI can be used as the quality control method for substance benchmark and lyophilized powder and dispensing granules of classical famous formulas with advantages of high sensitivity, strong analytical ability, no complex sample pretreatment, qualitative and relative content analysis of complex samples without reference substance.
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Due to numerous obstacles such as complex matrices, real-time monitoring of complex reaction systems (, medicinal herb stewing system) has always been a challenge though great values for safe and rational use of drugs. Herein, facilitated by the potential ability on the tolerance of complex matrices of extractive electrospray ionization mass spectrometry, a device was established to realize continuous sampling and real-time quantitative analysis of herb stewing system for the first time. A complete analytical strategy, including data acquisition, data mining, and data evaluation was proposed and implemented with overcoming the usual difficulties in real-time mass spectrometry quantification. The complex Fuzi (the lateral root of )-meat stewing systems were real-timely monitored in 150 min by qualitative and quantitative analysis of the nine key alkaloids accurately. The results showed that the strategy worked perfectly and the toxicity of the systems were evaluated and predicated accordingly. Stewing with trotters effectively accelerated the detoxification of Fuzi soup and reduced the overall toxicity to 68%, which was recommended to be used practically for treating rheumatic arthritis and enhancing immunity. The established strategy was versatile, simple, and accurate, which would have a wide application prospect in real-time analysis and evaluation of various complex reaction systems.
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Understanding of the nephrotoxicity induced by drug candidates is vital to drug discovery and development. Herein, an metabolomics method based on air flow-assisted desorption electrospray ionization mass spectrometry imaging (AFADESI-MSI) was established for direct analysis of metabolites in renal tissue sections. This method was subsequently applied to investigate spatially resolved metabolic profile changes in rat kidney after the administration of aristolochic acid I, a known nephrotoxic drug, aimed to discover metabolites associated with nephrotoxicity. As a result, 38 metabolites related to the arginine-creatinine metabolic pathway, the urea cycle, the serine synthesis pathway, metabolism of lipids, choline, histamine, lysine, and adenosine triphosphate were significantly changed in the group treated with aristolochic acid I. These metabolites exhibited a unique distribution in rat kidney and a good spatial match with histopathological renal lesions. This study provides new insights into the mechanisms underlying aristolochic acids nephrotoxicity and demonstrates that AFADESI-MSI-based metabolomics is a promising technique for investigation of the molecular mechanism of drug toxicity.
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Development of rapid analytical methods and establishment of toxic component limitation standards are of great importance in quality control of traditional Chinese medicine. Herein, an on-line extraction electrospray ionization mass spectrometry (oEESI-MS) coupled with a novel whole process integral quantification strategy was developed and applied to direct determination of nine key aconitine-type alkaloids in 20 proprietary Chinese medicines (APCMs). Multi-type dosage forms (, tablets, capsules, pills, granules, and liquid preparation) of APCM could be determined directly with excellent versatility. The strategy has the characteristics of high throughput, good tolerance of matrix interference, small amount of sample (∼0.5 mg) and reagent (∼240 μL) consumption, and short analysis time for single sample (<15 min). The results were proved to be credible by high performance liquid chromatography-mass spectrometry (LC-MS) and electrospray ionization mass spectrometry, respectively. Moreover, the limitation standard for the toxic aconitines in 20 APCMs was established based on the holistic weight toxicity (HWT) evaluation and the severally, and turned out that HWT-based toxicity evaluation results were closer to the real clinical applications. Hence, a more accurate and reliable APCM toxicity limitation was established and expected to play an important guiding role in clinics. The current study extended the power of ambient MS as a method for the direct quantification of molecules in complex samples, which is commonly required in pharmaceutical analysis, food safety control, public security, and many other disciplines.
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The current study reports on a mass spectrometric method for the quantification of gemfibrozil drug substance in itsformulation. Isocratic method was used for separation with help of Zorbax SB C18 column (4.6 × 50 mm, 3 µm) using atriple quadrupole mass detector in multiple reaction monitoring (MRM) mode and electrospray ionization as ionizationsource. The resulting runtime was found to be 3 minutes and the analyte elutes at 1.201 minutes 10-mM ammoniumformate was adjusted to pH 3.5: methanol (20:80 V/V) was used as mobile phase. Increased sensitivity from selectiveion monitoring (SIM) to MRM resulted in decreased quantitation limit (LOQ) and 0.5 ng/ml as detection limit (LOD).The method was validated in a range of 1–50 ng/ml and a correlation coefficient of 0.999. The method recoverywas found to be in the range of 94.03 % to 100.02 %. The developed method was validated as per the InternationalConference on Harmonisation (ICH) guidelines
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Objective: Both Lycium barbarum L. (LB) and Lycium ruthenicum Murr. (LR) belong to the Lycium genus of Solanaceae family but their fruits have significant phenotypic differences in terms of color and shapes. This study is aimed to investigate the inter-species difference of their fruit polyphenol composition. Methods: The polyphenol composition of fresh and dried fruits of two Lycium species were comprehensively analyzed using ultra-high performance liquid chromatography-electrospray ionization-quadrupole-time of flight mass spectrometry (UHPLC-ESIQ- TOF-MS). Results: 35 polyphenolic compounds were detected and quantified in the fresh and dried Lycium fruits including phenolic acids, anthocyanins and phenolamides (i.e., the amide-adducts of polyphenolic acids and polyamines). For both species, the dried fruits had more polyphenolic compounds than their fresh fruits with significant inter-species difference; for both fresh and dried fruits, LR had more polyphenolic compounds than LB. Conclusion: There are significant inter-species differences between these two Lycium in both fresh and dried fruits. These results offer essential information for further understanding of the biological functions of these two Lycium fruits as phytomedicines and functional food.
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OBJECTIVE@#The present study aimed to quantify and identify the bioactive compounds of the Arbutus unedo L. leaves in order to evaluate both their antioxidant properties and litholytic activities against calcium oxalate stones.@*METHODS@#This survey was carried out using hydroalcoholic extract (E.FA) and infusion (I.FA) of A. unedo leaves. The quantification of phenolic compounds, flavonoids, flavonols and anthocyanins was done by spectrophotometric methods and identification of chemical components was performed by ultra-performance liquid chromatography with photodiode array and electrospray ionization tandem mass spectrometry. Antioxidant activity was measured using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method and by the ferric reducing/antioxidant power (FRAP) assay. Litholytic activity of E.FA and I.FA was studied using a special model that resembles circuitry of the urinary system.@*RESULTS@#E.FA showed greater antioxidant efficacy than I.FA (P < 0.05). Its higher efficiency was shown via the values of median inhibitory concentration, which was close to (76.14 ± 0.91) µg/mL for E.FA versus (202.64 ± 5.77) μg/mL for I.FA using the DPPH method, and (53.77 ± 0.81) μg/mL for E.FA versus (236.86 ± 31.90) μg/mL for I.FA, using FRAP method. I.FA exhibited significantly higher litholytic activity compared to E.FA (P < 0.05), with dissolution values of 31.03% ± 0.63% versus 14.55% ± 0.65%, respectively.@*CONCLUSION@#Overall, the results suggest that the A. unedo is rich in bioactive compounds, and possesses antioxidant and litholitic abilities that are worthy of further study.
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Objective: To evaluate the effect of manual decocting and machine decocting on the chemical constituents in Bazhentang based on non-targeted metabolomics, and to find the differential chemical constituents of these two decocting methods. Method: Bazhentang was boiled by standardized manual decocting and machine decocting methods,respectively. Orthogonal partial least square-discriminate analysis(OPLS-DA) and other multivariate statistical methods, combined with variable importance in the projection(VIP) value and t-test, were employed to analyze the effect of two decocting methods on the chemical constituents in Bazhentang. The differential chemical constituents were analyzed by UPLC-LTQ-Orbitrap MS under positive and negative ion modes,mobile phase was acetonitrile-0.1%formic acid aqueous solution for gradient elution,the scanning range was m/z 50-1 500. Result: Under the positive and negative ion modes of high-resolution mass spectrometry, a total of 87 differential components were found,40 of them were identified according to the mass spectrometry data and literature reports, including senkyunolide A, glycyrrhizin, ferulic acid, etc. Conclusion: Based on the analysis of color and chemical compositions of Bazhentang, there are obvious differences between the standardized manual decocting and machine decocting. If the advantages of these two methods are combined,a standardized decoction process can be established on the basis of maintaining the advantages of manual decocting, the effectiveness of traditional Chinese medicine decoction will be maximized and it will be convenient for patients to take it.
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The tandem mass spectrum of apigenin-6,8-C-di-glucoside( 1) and apigenin-6-C-glucose-8-C-rhamnoside( 2) were obtained by high resolution electrospray ionization mass spectrometry( HR-ESI-MS/MS) in both positive and negative ion modes. The elemental composition of each ion was determined according to its accurate mass-to-charge,hence,the fragmentation pathways of each compound were proposed in both negative and positive ion modes. Comprehensive analysis of each ion and its proposed fragmentation pathways of the two compounds was initially conducted in both negative and positive ion mode HR-ESI-MS/MS to explore the diagnostic ions for flavone-6,8-C-di-glycosides and the characteristic ions for each compound and their cleavage rules. The results showed that a family of fragmentation ions with m/z 353,325,311,297 in ESI(-)-MS and m/z 355,325,307,295 in ESI( +)-MS could be the diagnostic ions of flavone-6,8-C-di-glycoside,and characteristic neutral loss could be assigned to glycosyl substitution,for example,neutral losses of C_4H_8O_4( 120),C_3H_6O_3( 90),C_2H_4O_2( 60) for glucoside substitution while neutral losses of C_4H_8O_3(104),C_3H_6O_2( 74),C_2H_4O( 44) for rhamnoside substitution. Furthermore,only one H_2O loss from mother ion( [M-H]-) was observed for 1 & 2 in ESI(-)-MS while five to six H2 O loss from mother ion( [M+H]+) was observed for 1 & 2 in ESI( +)-MS to produce a family of ions by subsequent loss of H_2O,which could be applied for glucosyl difference. The flavone-6,8-C-di-glycosides in both ESI( +)-MS and ESI(-)-MS showed the cleavage similarity at sugar substitutions. However,there were much more differences by the fragmentation pathways and neutral losses between ESI( +)-MS and ESI(-)-MS as following,hyperconjugation ions by subsequent loss of H_2O from precursor ions of flavone-6,8-C-di-glycosides in ESI( +)-MS were not observed in ESI(-)-MS; the subsequent neutral loss of CH_2O in ESI( +)-MS were rarely observed in ESI(-)-MS; the loss of CO only happen at C-ring of flavone ESI( +)-MS other than glycosyl position in ESI(-)-MS; the C4-chain neutral loss of flavone-6,8-C-di-glycosides happened at 8-C-glycosyl position other than at 6-C-glycosyl position. The above cleavage rules and diagnostic ions of ESI( +)-MS were successfully applied for the structure identification of 4 flavone-6 C,8 C-diglycosides from the stem extract of Dendrobium officinale as vicenin Ⅱ,vicenin Ⅰ,isoschaftoside,schaftoside as well as one flavone-O-glysoside named rutin,which were supported by ESI(-)-MS data as well.