RESUMEN
ObjectiveTo establish an ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry（UHPLC-QqQ-MS） for determination of the active ingredients in Erdongtang， and to predict the targets and pathways of anti-insulin resistance action of this formula. MethodThe analysis was performed on an ACQUITY UPLC BEH C18 column（2.1 mm×100 mm， 1.7 μm） with the mobile phase of 0.1% formic acid aqueous solution（A）-acetonitrile（B） for gradient elution（0-3 min， 90%-87%A； 3-6 min， 87%-86%A； 6-9 min， 86%-83%A； 9-11 min， 83%-75%A； 11-18 min， 75%-70%A； 18-19 min， 70%-52%A； 19-22 min， 52%A； 22-25 min， 52%-5%A； 25-27 min， 5%-90%A； 27-30 min， 90%A）. The contents of active ingredients in Erdongtang was detected by electrospray ionization（ESI） and multiple reaction monitoring（MRM） mode under positive and negative ion modes. On this basis， network pharmacology was applied to predict the targets and pathways of Erdongtang exerting anti-insulin resistance effect. ResultThe 20 active ingredients in Erdongtang showed good linear relationships within a certain mass concentration range， and the precision， stability， repeatability and recovery rate were good. The results of determination showed that the ingredients with high content in 15 batches of samples were baicalein（1 259.39-1 635.78 mg·L-1）， baicalin（1 078.37-1 411.52 mg·L-1）， the ingredients with medium content were mangiferin（148.59-217.04 mg·L-1）， timosaponin BⅡ（245.10-604.89 mg·L-1）， quercetin-3-O-glucuronide（89.30-423.26 mg·L-1）， rutin（46.91-1 553.61 mg·L-1）， glycyrrhizic acid（55.97-391.47 mg·L-1）， neomangiferin（37.45-127.03 mg·L-1）， nuciferine（0.89-63.48 mg·L-1）， hyperoside（6.96-136.78 mg·L-1）， liquiritin（30.89-122.78 mg·L-1）， liquiritigenin（26.64-110.67 mg·L-1）， protodioscin（58.57-284.26 mg·L-1）， the ingredients with low content were wogonin（7.16-20.74 mg·L-1）， pseudoprotodioscin（5.49-22.96 mg·L-1）， ginsenoside Rb1（7.31-23.87 mg·L-1）， ginsenoside Rg1（10.78-28.33 mg·L-1）， ginsenoside Re（7.78-24.76 mg·L-1）， ophiopogonin D（2.08-4.29 mg·L-1）， methylophiopogonanone A（0.74-1.67 mg·L-1）. The results of network pharmacology indicated that the mechanism of anti-insulin resistance exerted by Erdongtang might be related to the phosphatidylinositol 3-kinase/protein kinase B（PI3K/Akt） signaling pathway. ConclusionThe established UHPLC-QqQ-MS has the advantages of simple sample processing， strong exclusivity and high sensitivity， and can simultaneously determine the contents of the main ingredients from seven herbs in Erdongtang， which can lay the foundation for the development of Erdongtang compound preparations. The results of the network pharmacology can provide a reference for the mechanism study of Erdongtang in the treatment of type 2 diabetes mellitus.
RESUMEN
ObjectiveBased on ultra performance liquid chromatography-quadrupole-time-of-flight tandem mass spectrometry（UPLC-Q-TOF-MS）， to evaluate the establishment of a mouse model of liver Yin deficiency by thyroid tablet suspension combined with 10% carbon tetrachloride（CCl4） from the perspective of non-targeted metabolomics， in order to lay the foundation for the establishment of a traditional Chinese medicine（TCM） syndrome model. MethodA total of 24 mice were randomly divided into blank group and model group. The model group was given thyroid tablet suspension（0.003 2 g·kg-1） by gavage for 14 consecutive days， and 10% CCl4（5 mL·kg-1） was intraperitoneally injected once a week to establish a liver Yin deficiency model， while the blank group was injected with an equal amount of olive oil intraperitoneally and gavaged with an equal amount of distilled water， and was fed with normal feed. After the modeling was completed， 6 mice in each group were randomly selected， the levels of alanine aminotransferase（ALT）， aspartate aminotransferase（AST）， cyclic adenosine monophosphate（cAMP）， cyclic guanosine monophosphate（cGMP）， interleukin（IL）-6， IL-10， tumor necrosis factor-α（TNF-α）were measured in the mice serum， and malondialdehyde（MDA）， superoxide dismutase（SOD）， total protein（TP）， hydroxyproline（HYP） and other indicators were measured in the mice liver. Liver tissue sections were taken for hematoxylin-eosin（HE） staining and observing pathological changes. The remaining 6 mice in each group were subjected to UPLC-Q-TOF-MS combined with principal component analysis（PCA） and orthogonal partial least squares-discriminant analysis（OPLS-DA） were used to screen differential metabolites in the liver Yin deficiency mouse model， Kyoto Encyclopedia of Genes and Genomes（KEGG） database was used to analyze the corresponding metabolic pathways of differential metabolites. ResultCompared with the blank group， mice in the model group showed liver Yin deficiency manifestations such as reduced body weight， fatigue and sleepiness， disheveled and lusterless hair， irritability. The levels of ALT， cAMP/cGMP， IL-6， AST， MDA， cAMP， TNF-α significantly increased（P<0.05， P<0.01）， while the levels of SOD， IL-10 and cGMP significantly decreased（P<0.05， P<0.01）， and the changes of HYP and TP were not statistically significant. Hepatic steatosis and distortion of the radial arrangement of the liver plate cells were seen in the section images of the model group， endogenous substances were clearly separated， and 252 differential metabolites were identified in the serum samples， which were mainly involved in the metabolic pathways of purine metabolism， steroid hormone biosynthesis and pyrimidine metabolism. A total of 229 differential metabolites were identified in the liver samples， mainly involving nucleotide metabolism， purine metabolism， steroid hormone biosynthesis， pyrimidine metabolism， antifolate resistance， insulin resistance， primary bile acid biosynthesis， prostate cancer， sulfur relay system， arachidonic acid metabolism and other metabolic pathways. ConclusionThe successful establishment of liver Yin deficiency model in mice by CCl4 combined with thyroid hormone is evaluated through the investigation of serum and liver metabolomics， combined with biochemical indicators， which provides a biological basis and experimental foundation for the Yin deficiency syndrome model of TCM.
RESUMEN
Background Volatile organic compounds (VOCs) in exhaled breath are closely associated with respiratory diseases and are linked to various metabolic reactions in the human body. A quantitative analytical method can provide technical support for studying VOCs related to various diseases. Objective To establish a thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) method for the determination of 27 VOCs in exhaled breath. Methods VOCs in exhaled breath were collected using a Bio-VOC sampler and enriched with Tenax TA thermal desorption tubes before TD-GC-MS analysis. Standards were collected using thermal desorption tubes and optimized for thermal desorption conditions as well as chromatographic and mass spectrometric conditions: The separation of the 27 VOCs was achieved by an optimized temperature program, the improvement of sensitivity by optimizing quantitative ions, and the increase of VOCs desorption efficiency by optimizing thermal desorption time and temperature. Limit of detection, limit of quantification, accuracy, precision, and stability of the proposed method were investigated by spiking with a blank gas bag, and exhaled breath samples from 20 healthy individuals were collected for an application study of the proposed method. Results The thermal desorption temperature was 280 ℃, and desorption time was 6 min. A VF-624ms chromatographic column was selected for the separation of target substances. The initial temperature of heating program was 35 ℃, maintained for 1 min, and then increased to 100 ℃ at a heating rate of 3 ℃·min−1 for 1 min, followed by increasing to 210 ℃ at a heating rate of 28 ℃·min−1 for 5 min. A quantitative analysis was conducted with a single ion monitoring (SIM) mode. Under these conditions, the 27 VOCs showed good linear relationships in their respective concentration ranges and the correlation coefficients were higher than 0.9990. The limits of detection of the method were in the range of 0.01-0.13 nmol·mol−1, the limits of quantification were in the range of 0.02-0.44 nmol·mol−1, and the spiked recoveries were in the range of 80.1%-120.5%, with intra-batch and inter-batch precision ≤ 18.8% and 17.9% respectively. All substances can be stored at room temperature (23-28 °C) for 7 d and at 4 °C for 14 d. The proposed method was applied to exhaled breath samples from 20 subjects with detection rates≥ 80% (except for trans-2-pentene and decane) and a concentration range of 0.00-465.50 nmol·mol−1. Conclusion The established TD-GC-MS method for quantification of VOCs in exhaled breath is characterized by high sensitivity and good accuracy, and is suitable for quantitative determination of VOCs in exhaled breath, which can provide technical support for the study of exhaled breath VOCs.
RESUMEN
ObjectiveTo investigate the mechanism of Atractylodis Macrocephalae Rhizoma（AMR） in the treatment of slow-transmission constipation（STC） by observing the effects of AMR on short-chain fatty acids and intestinal barries in STC mice. MethodForty-eight male KM mice were randomly divided into blank group， model group， AMR low-， medium-， high-dose groups（2.5， 5， 10 g·kg-1） and mosapride group（2.5 mg·kg-1）. Except for the blank group， all groups were gavaged with loperamide suspension（5 mg·kg-1） twice daily for 14 d to construct the STC mouse model. At the same time， each drug administration group was given the corresponding drug by gavage for consecutive 14 d， the blank and model groups were gavaged with equal volume of distilled water. The effects of the treatment of AMR on body mass， defecation frequency， fecal water content and intestinal propulsion rate of mice were observed， the pathological changes of mouse colon were observed by hematoxylin-eosin（HE） staining and periodic acid-Schiff（PAS） staining， the levels of gastrin（GAS） and motilin（MTL） in serum were detected by enzyme-linked immunosorbent assay（ELISA）， gas chromatography-mass spectrometry（GC-MS） was used to detect the contents of short-chain fatty acids（SCFAs） in mouse feces， real-time fluorescence quantitative polymerase chain reaction（Real-time PCR） and Western blot were used to determine the mRNA and protein expression levels of zonula occludens-1（ZO-1）， Occludin， and Claudin-1 in the colon of mice. ResultCompared with the blank group， the body mass， defecation frequency， fecal water content and intestinal propulsion rate of mice in the model group were significantly decreased（P<0.05， P<0.01）， the arrangement of colonic tissues was disordered， and the number of goblet cells was reduced， the levels of GAS and MTL in serum were significantly decreased（P<0.01）， and the levels of SCFAs in the feces were on a decreasing trend， with the contents of acetic acid， propionic acid， butyric acid， isobutyric acid and valeric acid were significantly decreased（P<0.05， P<0.01）， the mRNA and protein expression levels of ZO-1， Occludin and Claudin-1 in the colonic tissues were significantly decreased（P<0.01）. The above results suggested that STC mouse model was successfully constructed. Compared with the model group， the body mass， defecation frequency， fecal water content and intestinal propulsion rate of mice in AMP administration groups all increased significantly（P<0.05， P<0.01）， the mucosal layer of the colonic tissues was structurally intact without obvious damage， and the number of goblet cells increased， serum levels of GAS and MTL were significantly increased（P<0.01）， the contents of SCFAs in the feces were all on a rising trend， with the contents of acetic， propionic， butyric and isobutyric acids rising significantly（P<0.05， P<0.01）， the mRNA and protein expression levels of ZO-1， Occludin and Claudin-1 in the colonic tissues were significantly increased（P<0.05， P<0.01）. ConclusionAMR is able to improve the constipation symptoms in STC mice， and its mechanism may be related to increasing the contents of SCFAs in the intestine as well as promoting the mRNA and protein expression levels of ZO-1， Occludin and Claudin-1 in the colon.
RESUMEN
ObjectiveTo establish a qualitative and quantitative analysis method for chemical constituents in Liu Junzitang（LJZT）， and to clarify its material basis. MethodThe chemical constituents in LJZT were analyzed by ultra performance liquid chromatography-quadrupole-time-of-flight mass spectrometry（UPLC-Q-TOF-MS/MS）， and the resulting compounds were identified by using databases， such as MassBank， PubChem， ChemSpider， Traditional Chinese Medicine Systems Pharmacology Database and Analytical Platform（TCMSP）， and by combining with relevant literature. UPLC was used to establish a quantitative method for analysis of 9 compounds in LJZT， including liquiritin， hesperidin， lobetyolin， liquiritigenin， glycyrrhizic acid， nobiletin， tangeretin， atractylenolide Ⅱ and Ⅰ. ResultBy combining the relevant literature， database and MS information， a total of 79 compounds were identified from LJZT， including 31 flavonoids， 15 terpenoids， 14 nitrogen-containing compounds， 6 phenylpropanoids， 6 organic acids and 7 other compounds. The established quantitative analytical method for the nine representative components showed good linearity within their respective linear ranges， and the precision， stability， reproducibility and recovery were in accordance with the requirements. The quantitative results showed that the contents of liquiritin， hesperidin， lobetyolin， liquiritigenin， glycyrrhizic acid， nobiletin， tangeretin， atractylenolide Ⅱ and Ⅰ in LJZT were 0.376 5， 2.602 1， 0.082 6， 0.128 1， 1.778 6， 0.015 7， 0.006 7， 0.030 4， 0.003 2 mg·g-1， respectively. ConclusionThe established method can quickly， sensitively and accurately analyze the chemical constituents in LJZT， clarify that the material basis of LJZT is mainly flavonoids， terpenoids and nitrogen-containing compounds， and simultaneously determine the contents of the 9 components， which can lay a foundation for the research on quality control， mechanism and clinical application of LJZT.
RESUMEN
Background Per- and polyfluoroalkyl substances (PFAS) are a class of persistent organic pollutants that possess potential toxicity to the human body. The production and utilization of diverse emerging PFAS have resulted in widespread human exposure. Therefore, it is imperative to establish a quantitative methodology encompassing a wide range of PFAS for a comprehensive assessment of human exposure to these compounds. Objective To establish a high-throughput quantitative method for the simultaneous determination of 53 PFAS in human serum based on ultra-high-performance liquid chromatography-Q Exactive high resolution mass spectrometry (UPLC-Q Exactive HRMS). Methods The extraction recoveries of hydrophilic-lipophilic balance (HLB) column, weak anionexchange (WAX) column, and 96-well WAX μElution plate were compared to select the SPE column with the highest recovery. The retention time and peak shape of the target compounds were compared between ACQUITY UPLC BEH C18 column and Accucore aQ column, and the more cost-effective column was chosen. The effects of adding different levels of ammonium formate (0, 2, 5 and 10 mmol·L−1) in mobile phase on peak shape and target response were compared to determine the optimal buffer salt concentration. The optimal spray voltage was obtained by comparing −2 kV and −4 kV. The proposed method was validated from the aspects of selectivity, standard curve, limits of detection, precision, accuracy, and matrix effect. The method was applied to 142 umbilical serum samples. Results The best recovery rate (64%-118%) was achieved by using 96-well WAX μElution plate. The optimal separation and peak shape were obtained by utilizing Accucore aQ column with H2O-methanol (containing 5 mmol·L−1 ammonium formate) as the mobile phase. Less in-source collision and better target response were observed when the spray voltage was set to −2 kV. All target analytes had a good linearity, with R2 > 0.99. The limits of detection ranged from 0.01 to 0.50 μg·L−1, and the recovery ranged from 69% to 127% with the precision less than 26%. A total of 31 PFAS were detected in the 142 actual samples, among which 14 PFAS had a detection frequency over 50%. Perfluorooctanoic acid showed the highest median concentration of 4.16 μg·L−1, followed by 6:2 chlorinated polyfluorinated ether sulfonate and perfluorooctane sulfonates (3.50 μg·L−1 and 1.59 μg·L−1, respectively). Conclusion In this study, we establish a UPLC-Q Excative HRMS method for simutanious determination of 53 PFAS concentrations in serum. This method has the advantages of wide coverage of PFAS, good selectivity, and easy operation, and is suitable for biological detection with a large sample size.
RESUMEN
ObjectiveUltra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry（UPLC-Q-TOF-MS） was used to identify the metabolites of harmine in rats， in order to explore the differences in distribution of metabolites in rats after single dose（40 mg·kg-1） intragastric administration of harmine， as well to speculate the metabolic pathways. MethodSD rats were given a single dose of harmine by intragastric administration. Plasma， bile， urine and feces samples were collected after administration， and the samples were processed for determination by UPLC-Q-TOF-MS. The separation was performed on an ACQUITY UPLC™ HSS T3 columu（2.1 mm×100 mm， 1.8 μm） with acetonitrile（A）-0.1% formic acid aqueous solution（B） as mobile phase for gradient elution（0-2 min， 5%A； 2-9 min， 5%-35%A； 9-9.5 min， 35%-100%A； 9.5-12 min， 100%A； 12-12.5 min， 100%-5%A； 12.5-14 min， 5%A）， the mass spectra were obtained in positive ion mode with electrospray ionization（ESI）， the scanning range was m/z 50-1 200. The metabolites of harmine were identified based on the information of the obtained compounds and the literature data， and the metabolic pathways were hypothesized. ResultA total of 42 compounds（harmine and its metabolites） were identified in rats， including 27 in plasma， 17 in bile， 26 in urine and 13 in feces. The metabolic pathways involved in these 42 metabolites included monohydroxylation， dihydroxylation， demethylation， glucuronidation and sulfation. ConclusionHarmine can undergo phase Ⅰ and phase Ⅱ metabolic reactions in rats， and the prototype drug is metabolized rapidly in vivo， and the metabolites are mainly excreted by the kidneys， which can provide a reference basis for the pharmacodynamics and material basis of harmine.
RESUMEN
@#Abstract: The differential expression and subcellular localization of single-cell proteins are closely related to the physiological state and pathological mechanisms of the body. The development of single-cell protein in situ imaging methods provides powerful tools for spatial single-cell proteomics research and single-cell protein profiling. This article summarizes the single-cell protein imaging methods developed in recent years, including the circulating immunofluorescence imaging methods based on ordered multi-round antibody incubation, mass spectrometry imaging based on metal element labeled antibodies, fluorescence imaging based on DNA-barcoded antibody, gene encoded fluorescence protein imaging and spectral imaging based on Raman spectroscopy or X-ray spectroscopy, with brief explanation of the imaging principles of these methods. It focuses on the multiple performance, imaging resolution and signal amplification performance of these methods, and analyzes their application characteristics in practical scientific research and clinical work, in the hope of providing some reference for the development of more revolutionary single-cell imaging methods, and promoting the development of biomedical and precision medicine.
RESUMEN
ObjectiveTo investigate the brain absorption components of Tianyuan Zhitong prescription and their distribution based on ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry（UPLC-Q-TOF-MS）， desorption electrospray ionization mass spectrometry imaging（DESI-MSI） and hyperspectral imaging techniques. MethodTen BALB/c mice were randomly divided into blank group（n=3） and administration group（n=7）， the administration group was gavaged with 0.3 mL of Tianyuan Zhitong prescription liquid at a concentration of about 5 g·mL-1 of the raw material， and the blank group was gavaged with an equal volume of normal saline， and the whole brain of the mice were taken for the preparation of tissue homogenates and frozen sections， respectively. The tissue homogenates were qualitatively analyzed by UPLC-Q-TOF-MS for the brain absorption components in positive and negative ion modes， frozen sections were used for imaging to observe the distribution of these components in the brain. Cytoviva dark-field enhancement microscope was used to perform hyperspectral imaging scanning on the brain sections of mice from each group， and the scattered light data of at least 1 000 pixels in the visible-near-infrared（400-1 000 nm） band in the microscopic field of view were collected and average spectrum were created， which were used to compare the components in the brain tissues of mice from the blank and administration groups. ResultA total of 27 brain absorption components of Tianyuan Zhitong prescription were identified by UPLC-Q-TOF-MS， including 10 organic acids， 5 glycosides， 4 alkaloids， 1 phenol， 4 flavonoids， 2 phthalides and 1 other compound， which were mainly derived from Gastrodiae Rhizoma， Chuanxiong Rhizoma， vinegar-processed Corydalis Rhizoma， Ziziphi Spinosae Semen and processed Morindae Officinalis Radix. A total of 14 components were identified by mass spectrometry imaging， of which ferulic acid， tetrahydropalmatine and N-methyl dehydroberberine were mainly distributed in the cerebral cortex， vitamin B5， vemonoic acid and ricinoleic acid were mainly distributed in the hypothalamus， elemicin， octadecenic acid and octadecanoic acid were mainly distributed in the cortex and hypothalamus， while senkyunolide B， ligustilide， linoleic acid， 9，12-octadecadienoyl ethyl ester and spinosin were distributed in most regions of the brain tissues. Hyperspectral imaging showed that in the visible-near-infrared band range， the average spectrum of the brain tissues of mice in the administration group was significantly red-shifted， indicating that there were differences in the physical properties or contents of the chemical components in the brain between mice in the blank group and those in the administration group， and further verified the results of mass spectrometry imaging. ConclusionThrough the combination of UPLC-Q-TOF-MS and imaging techniques， the pharmacodynamic components of Tianyuan Zhitong prescription in the treatment of headache and the regional characteristics in brain tissue are clarified， which can provide reference for the selection of the index components of the research on the quality standard of this prescription and the research on the mechanism of the pharmacological effect.
RESUMEN
ObjectiveTo investigate the mechanism of anti-pulmonary fibrosis of cannabidiol by ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry（UPLC-Q-TOF-MS）. MethodSD rats were randomly divided into blank group， model group， prednisone group（3.15 mg·kg-1） and cannabidiol low， medium and high dose groups（12， 36， 108 mg·kg-1）， with 8 rats in each group. The rat model of pulmonary fibrosis was established by intratracheal injection of bleomycin（5 mg·kg-1）， which was administered continuously for 28 days after successful modeling. The pathological changes of rat lung tissue were observed， and enzyme-linked immunosorbent assay（ELISA） was used to detect the expression levels of matrix metalloproteinase-7（MMP-7）， type Ⅱ alveolar cell surface antigen（KL-6）， pulmonary surfactant-associated protein A（SP-A） and SP-D in serum. The expression levels of type Ⅰ collagen（Col-Ⅰ） and fibronectin（FN） in lung tissues were detected by immunohistochemistry， and the expression of mucin 5 subtype AC（MUC5AC） was detected by immunofluorescence. UPLC-Q-TOF-MS was used to search for potential biomarkers and related metabolic pathways of cannabidiol in treating pulmonary fibrosis. ResultCompared with the blank group， there were a large number of inflammatory cell infiltration and continuous fibrosis lesions in the lung tissue of rats in the model group. Compared with the model group， the inflammatory infiltration and blue collagen deposition in the lung tissue of rats in the prednisone and cannabidiol groups were reduced. Compared with the blank group， the expressions of MMP-7， KL-6， SP-A and SP-D in serum of the model group were significantly increased（P<0.01）， while the expressions of MMP-7， KL-6， SP-A and SP-D in the prednisone and cannabidiol high dose groups were significantly decreased by comparing with the model group（P<0.05， P<0.01）. Compared with the blank group， the expression levels of Col-Ⅰ and FN in the lung tissues of the model group were significantly increased， and the fluorescence intensity of MUC5AC was significantly increased（P<0.01）. Compared with the model group， the expression levels of Col-Ⅰ and FN in the lung tissues of the prednisone and cannabidiol high dose groups were significantly decreased（P<0.05， P<0.01）， and the expression of MUC5AC was significantly decreased（P<0.01）. Compared with the blank group， a total of 18 differential compounds were screened out in the model group， which could be used as potential biomarkers， and cannabidiol could call back 16 of them， mainly involving 4 metabolic pathways（linoleic acid metabolism， phenylalanine， tyrosine and tryptophan biosynthesis， arachidonic acid metabolism， and niacin and niacinamide metabolism）. Compared with the blank group， the relative contents of potential biomarkers arachidonic acid and linoleic acid were significantly increased in the model group（P<0.05， P<0.01）， while the relative contents of 5，6-EET， L-tyrosine and niacinamide were significantly decreased（P<0.01）. Compared with the model group， cannabidiol could significantly reduce the relative contents of arachidonic acid and linoleic acid， and significantly increase the relative contents of 5，6-EET， L-tyrosine and niacinamide（P<0.01）. ConclusionCannabidiol has an intervention and remission effect on pulmonary fibrosis， and its mechanism may be related to linoleic acid metabolism， phenylalanine， tyrosine and tryptophan biosynthesis， arachidonic acid metabolism， niacin and niacinamide metabolism.
RESUMEN
A derivatizaton method combined with gas chromatography-mass spectrometry(GC-MS)was established for detection of isobutyl chloroformate(IBCF)residue in active pharmaceutical ingredient of agatroban.The extraction and derivatization reagents,derivatization time,qualitative and quantitative ions were selected and optimized,respectively.The possible mechanism of derivatization and characteristic fragment ions fragmentation were speculated.The agatroban samples were dissolved and extracted by methanol,and the residual IBCF was derived with methanol to generate methyl isobutyl carbonate(MIBCB).After 24 h static derivatization at room temperature,IBCF was completely transformed into MIBCB,which could be used to indirectly detect IBCF accurately.The results showed that the linearity of this method was good in the range of 25-500 ng/mL(R2=0.9999).The limit of detection(LOD,S/N=3)was 0.75 μg/g,and the limit of quantification(LOQ,S/N=10)was 2.50 μg/g.Good recoveries(95.2%-97.8%)and relative standard deviations(RSDs)less than 3.1%(n=6)were obtained from agatroban samples at three spiked levels of IBCF(2.50,25.00,50.00 μg/g),which showed good accuracy of this method.Good precision of detection results was obtained by different laboratory technicians at different times,the mean value of spiked sample solution(25.00 μg/g)was 24.28 μg/g,and the RSD was 2.1%(n=12).The durability was good,minor changes of detection conditions had little effect on the results.Under the original condition and conditions with initial column temperature±5℃,heating rate±2℃/min,column flow rate±0.1 mL/min,the IBCF content of spiked sample solution(25.00 μg/g)was detected,the mean value of detection results was 24.16 μg/g,and the RSD was 2.2%(n=7).Eight batches of agatroban samples from two manufacturers were detected using the established method,and the results showed that no IBCF residue was detected in any of these samples.The agatroban samples could be dissolved by methanol,and then the IBCF residue could be simultaneously extracted and derived with methanol as well.This detection method had the advantages of simple operation,high sensitivity,low matrix effect and accurate quantification,which provided a new effective method for detection of IBCF residue in agatroban.
RESUMEN
A rapid analytical method for simultaneous determination of 32 kinds of multi-residue veterinary drugs in eggs was developed using a modified QuEChERS technique based on a reduced graphene oxide-coated melamine sponge(r-GO@MeS)by ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).The influences of graphene oxide(GO)concentrations,sponge dosages,and purification modes on drug recoveries were investigated during the purification process.The optimal purification conditions involved using a GO concentration of 0.5 mg/mL,a sponge dosage of 6.0 cm3/mL,and a dynamic purification mode of 5 extrusion cycles.Separation was achieved using an Agilent Eclipse Plus C18 RRHD column(100 mm×2.1 mm,1.8 μm),and quantitative analysis was performed by the external standard method using an electrospray ionization source(ESI)in multiple reaction monitoring(MRM)mode.The results showed that all 32 kinds of veterinary drugs exhibited good linear correlation with coefficients greater than 0.999,and matrix effects(MEs)ranging from?7.8%to 18.9%.The limits of detection(LODs)and quantification(LOQs)ranged from 0.2 to 10.2 μg/kg and from 0.6 to 28.0 μg/kg,respectively.The recoveries for the three spiked levels were in the range of 66.5%?117.5%,with intra-day and inter-day precision(Relative standard deviation)below 13.3%and 16.3%,respectively.The synthetic r-GO@MeS exhibited efficient matrix purification without the need of high-speed centrifugation or strong magnetic field assistance.This significantly shorted the sample pretreatment time and improved the convenience of the matrix purification process.Combined with UPLC-MS/MS,the method was suitable for the rapid determination of multi-residue veterinary drugs in eggs.
RESUMEN
Investigating the structural characteristics of proton tautomers is of great significance for understanding organic reactions and biochemical processes.In this study,a method based on ion mobility mass spectrometry combined with ab initio molecular dynamics calculations was proposed.The structures of proton tautomers were determined by comparing the experimental and theoretical collision-induced dissociation(CID)mass spectrograms of different proton tautomers.Ion mobility mass spectrometry was used to separate proton tautomerism produced during ionization.The CID mass spectra of each isomer could be obtained after mobility separation.The quantum chemical mass spectrometry(QCXMS)program based on ab initio molecular dynamics calculations was used to calculate the fragmentation process and obtain the theoretical CID mass spectra.The results of experiment and calculation showed that this method effectively solved the issue of difficult identification of proton tautomers.This method was also of great significance for the study of ionization mechanism and organic reaction process using mass spectrometry.
RESUMEN
A liquid chromatography-tandem mass spectrometry(LC-MS/MS)method was developed for determination of three kinds of β-agonists(Clenbuterol(CL),Ractopamine(RAC)and Salbutamol(SAL))residues in animal liver samples.The liver sample homogenates were extracted with organic solvent,followed by clean-up using the automatic magnetic solid-phase extraction(MSPE),and then analyzed using LC-MS/MS.The results showed that the magnetic mixed-mode cation exchange adsorbent(M-MCX)exhibited 34%higher adsorption capacity than the conventional mixed-mode cation exchange(MCX)column.Furthermore,the clean-up was conducted by using an automatic MSPE device,and 8 samples could be simultaneously treated within 30 min.The limits of detection(LOD)were 0.01-0.1 μg/kg,the average recoveries ranged from 88.2%to 110.5%,and the relative standard deviations(RSDs)were in range of 2.9%-10.3%at three spiked levels for the three kinds of β-agonists.Compared with the traditional SPE technique,the present method had many advantages such as simple operation,rapidity and high efficiency,which was suitable for high-throughput and automatic detection of residues in routine analysis.
RESUMEN
A new method for simultaneous determination of 23 kinds of per-and polyfluoroalkyl substances(PFASs)(13 kinds of perfluoro carboxylic acids,4 kinds of perfluoro sulfonic acids,and 6 kinds of new substitutes)in plant leaf tissue by ultra-high performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS)using automatic online solid phase extraction(SPE)to remove the matrix interference components in plant crude extracts was developed.The plant leaf samples were extracted twice with 1%formic acid-methanol solution,then evaporated to dry,redissolved with 70%methanol solution,and directly injected for analysis.After 23 kinds of target PFASs were purified automatically by online SPE with a WAX column,the six-way valve was switched to rinse PFASs onto an alkaline mobile phase system-compatible C18 analytical column.Then,the 23 kinds of target PFASs were separated within 16 min by gradient elution using a binary mobile phase system of methanol/water(Containing 0.4%ammonium hydroxide).Tandem mass spectrometry was performed in multiple reaction monitoring(MRM)mode for online detection of various PFASs,and quantification was carried out by internal standard method.The results of the method validation showed that satisfactory average recoveries of 23 kinds of PFASs in plant leaf samples(64.2%-125.5%),precision(relative standard deviations(RSDs)of 0.7%-12.8%),linearity(R2＞0.990),and sensitivity(the detection limits(S/N=3)were in the range of 0.02-0.50 μg/kg)were achieved.Finally,this method was used to detect PFASs in the marine green tide algae(Enteromorpha prolifera)and several tree leaves,and a total of 6 kinds of PFASs were detected,in which PFBA was the main contaminant.Compared with the reported offline SPE methods,the proposed online SPE technique significantly simplified the sample pretreatment process and provided an automatic,simple,and environment-friendly method for the routine monitoring of legacy and emerging PFASs in plant tissues.
RESUMEN
Objective To establish a rapid screening method for 34 emerging contaminants in surface water by ultra-high performance liquid chromatography-quadrupole-time of flight mass spectrometry(UHPLC-Q-TOF-MS).Methods The pretreatment conditions of solid phase extraction(SPE)were op-timized by orthogonal experimental design and the surface water samples were concentrated and ex-tracted by Oasis? HLB and Oasis? MCX SPE columns in series.The extracts were separated by Kine-tex? EVO C18 column,with gradient elution of 0.1%formic acid aqueous solution and 0.1%formic acid methanol solution.Q-TOF-MS'fullscan'and'targeted MS/MS'modes were used to detect 34 emerging contaminants and to establish a database with 34 emerging contaminants precursor ion,prod-uct ion and retention times.Results The 34 emerging contaminants exhibited good linearity in the con-centration range respectively and the correlation coefficients(r)were higher than 0.97.The limit of de-tection was 0.2-10 ng/L and the recoveries were 81.2%-119.2%.The intra-day precision was 0.78%-18.70%.The method was applied to analyze multiple surface water samples and 6 emerging contaminants were detected,with a concentration range of 1.93-157.71 ng/L.Conclusion The method is simple and rapid for screening various emerging contaminants at the trace level in surface water.
RESUMEN
Objective:To analyze the effects of processed Epimedii Folium on endogenous metabolites of mouse melanoma cells (B16 cells) before and after processing based on cell metabolomics; To investigate the changes of processed Epimedii Folium before and after processing.Methods:Ultra performance liquid chromatography tandem four-stage orbital trap mass spectrometry (UPLC-Q-Exactive Orbitrap-MS) technology was used, and the endogenous small molecules of B16 cells treated with Epimedii Folium and processed Epimedii Folium were analyzed by metabolomics. The differential metabolites between groups were obtained, and relevant metabolic pathways were analyzed based on the MetaboAnalyst 5.0 database.Results:Significant changes were observed in 13 kinds of endogenous metabolites, including alanine, carnitine C3∶0, glutamic acid-1, lactic acid, isoleucine, choline, phosphatidylcholine (34∶2, 36∶2), free fatty acids, citric acid, carnitine C4∶0, lysophosphatidylcholine 16∶0 and malic acid after the intervention of Epimedii Folium and processed Epimedii Folium. And the impact of processed products on differential metabolites was stronger than that of raw products. The main pathways involved were Warburg effect, pyruvate metabolism, malate-aspartic acid shuttle, pyruvaldehyde degradation and so on.Conclusions:Epimedii Folium and processed Epimedii Folium would have certain effects on cellular metabolic pathways. The results may be related to the pharmacological effects and changes in cold and hot properties of Epimedii Folium before and after processing.
RESUMEN
Objective To investigate the characteristic volatile organic compounds(VOCs)in exhaled breath and their diagnostic value in mice with early stage radiation injury.Methods The thermal desorption gas chromatography-mass spectrometry(TD-GC/MS)technique was used to analyze VOCs in exhaled breath of irradiated mice by 60Coγ-ray with 800 cGy.The characteristic VOCs in the early stage of radiation injury were identified,and a diagnostic model was established.Results The 30-day survival rate of mice was 4.2%.There were significant differences in characteristic VOCs at 7 hours after radiation injury,and thirty characteristic VOCs related to early-stage radiation injury were identified.The diagnostic value of differential metabolites in mice after irradiation was evaluated via the ROC curve,and the area under the ROC curve(AUC)of a single compound exceeded 0.8.The diagnostic model was constructed by screening 9 potential biomarkers of exhalation through Fisher discriminant analysis,and its sensitivity and specificity were close to 100%.Conclusion Analysis of VOCs in exhaled breath is expected to provide a non-invasive diagnostic method for early screening and diagnosis of radiation injury.
RESUMEN
Objective To evaluate the performance of the automated magnetic beads extraction method for extraction of serum fat-soluble vitamins by liquid chromatography-tandem mass spectrometry(LC-MS/MS).Methods A total of 120 clinical residual serum samples were collected automated magnetic beads extraction method was applied to extract serum fat-soluble vitamins A,D2,D3,E and K.The linearity,limit of quantification,precision,accuracy,carryover and matrix effect of fat-soluble vitamins A,D2,D3,E and K were detected by LC-MS/MS.The consistency of the method and conventional extraction method was compared.Results The linear correlation coefficients for extracting fat-soluble vitamins A,D2,D3,E and K by automated magnetic beads extraction method were all greater than 0.99,and the quantitative limits for these five fat-soluble vitamins were 5,0.25,0.25,125 and 0.025 ng/ml.The intra-batch precision and inter-batch precision were 0.66%～4.83%and 0.15%～3.70%,respectively,and the average spike recovery rate was 87.05%～111.11%.The matrix effect was 95.43%～99.07%,and the difference between the mean value of the cyclic injection results of high-low value samples and the mean value of the cyclic injection results of low-low value samples was less than 3s of the mean value of the cyclic injection results of low-low value samples.The statistical analysis showed that the correlation between the results of the automated magnetic beads extraction method and the conventional extraction method was good(r＞0.99),and there was no significant bias in the detection results of the two methods.Conclusion The automated magnetic beads extraction method for extraction of fat-soluble vitamins had good detection performance,which may be expected to improve sample flux and analysis efficiency.
RESUMEN
Objective The aim of this study was to screen and verify the proteins interacting with Vimentin,investigate the regulatory relationship between FABP5 and candidate proteins,and further explore the mechanism of FABP5 in hepatocellular carcinoma.Methods Immunoprecipitation combined with tandem mass spectrometry(IP-MS)was used to screen the proteins that bind to FABP5.The binding relationship between FABP5 and candi-date interacting proteins was verified from the exogenous and endogenous levels by Co-immune precipitation assay(Co-IP).RT-qPCR,Western blot and immunofluorescence were used to observe the effect of knockdown FABP5 on the transcription and translation of Vimentin in HCC cells.The effect of overexpressing FABP5 on the cytoskeleton of HCC cell was observed by phalloidin staining.Results 336 potential target proteins that bind to FABP5 were identi-fied through IP-MS.Based on literature,five candidate proteins related to tumors were selected,namely PRDX1,PRSS3,PKM,HSP90AA1,and Vimentin.The binding relationship between FABP5 and Vimentin protein was con-firmed through both exogenous and endogenous Co-IP.Knockdown FABP5 has no significant effect on the expression of Vimentin mRNA,but it can inhibit the expression of Vimentin protein,and overexpression of FABP5 can affect the cytoskeleton of HCC cell.Conclusions FABP5 promotes the migration and invasion of HCC cells by the regula-tion of Vimentin and the influence of cytoskeletal remodeling,and thus it is expected to be a potential target for anti-HCC and provide new ideas for the treatment of HCC.