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1.
Talanta ; 235: 122788, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517646

RESUMO

A thermal desorption associative ionization time-of-flight mass spectrometer was developed for ultrasensitive detection of semi-volatile chemical warfare agents (CWAs). The excited-state CH2Cl2-induced associative ionization method presented a soft ionization characterization and an excellent sensitivity towards CWAs. The detection sensitivities of the investigated nine CWA-related substances were 2.56 × 105-5.01 × 106 counts ng-1 in a detection cycle (30 s or 100 s). The corresponding 3σ limits of detection (LODs) were 0.08-3.90 pg. Compared with the best-documented LODs via the dielectric barrier discharge ionization (DBDI) and secondary electrospray ionization (SESI), the obtained LODs of the investigated compounds were improved by 2-76 times. Additionally, the measured sensitivity of 2-Chloroethyl ethyl, a proxy for mustard gas, is 550 counts pptv-1, which exceeds the DBDI and SESI's corresponding values (4.4 counts pptv-1 and 6.5 counts pptv-1) nearly by two orders of magnitude. A field application simulation was conducted by putting a strip of PTFE film contaminated with the CWA-related agent into the thermal desorption unit. The simulation showed that the sensitivities of the instrument via swipe surveying could achieve 2.19 × 105 to 5.23 × 106 counts ng-1. The experimental results demonstrate that the excited-state CH2Cl2-induced associative ionization is an ultrasensitive ionization method for CWAs and reveal a prospect for improving the detection of CWA species future.


Assuntos
Substâncias para a Guerra Química , Gás de Mostarda , Substâncias para a Guerra Química/análise , Limite de Detecção , Espectrometria de Massas , Gás de Mostarda/análise , Espectrometria de Massas por Ionização por Electrospray
2.
Talanta ; 235: 122804, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517662

RESUMO

Identifying the writing sequence of seals and signatures in documents is often performed and difficult to resolve in forensic determination. Morphological and physical-chemical analysis methods are often limited by the destructive nature of samples, a high signal response strength and specific materials. Mass spectrometry imaging (MSI) has been used as an alternative method because it can generate molecular images from many surfaces and produce rich chemical information. Herein, we developed a sequence identification method by coupling an air flow-assisted desorption electrospray ionization (AFADESI)-MSI system with a chemometric analysis, which can holistically and directly analyse document samples under ambient, moderate and selectable conditions and maintain the original appearance of the paper documents after sampling. By integrating principal component analysis (PCA) and the partial least squares discriminant analysis (PLS-DA), equivocal point analysis can be objectively performed, where knowing the components of the seal or signature is not necessary to identify the sequence. In total, 28 prepared samples with known sequences and two original blind test samples were analysed. One prepared sample was analysed in negative ionization mode, and other samples were inferred in positive ionization mode. All writing sequences were in accordance with the actual case. The writing sequence of the blind testing of the original samples was correctly identified. This study provided a convenient, objective and quasi-nondestructive method to investigate the sequence differences among equivocal document samples and is promising for providing an alternative method for the sequence identification of seals and signatures in questionable documents.


Assuntos
Espectrometria de Massas por Ionização por Electrospray , Redação , Análise Discriminante , Análise dos Mínimos Quadrados , Espectrometria de Massas , Análise de Componente Principal
3.
Talanta ; 235: 122816, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517672

RESUMO

In recent years, the development of unsaturated lipid isomeric imaging based on the Paternò-Büchi (PB) reaction has improved significantly. However, research on this imaging method in ambient conditions needs to expand. In this paper, a method of PB reaction in the solid phase in ambient conditions is developed, which is combined with air-flow-assisted desorption electrospray ionisation mass spectrometry (AFADESI-MS) to achieve in situ imaging of lipids at an isomeric level. Experiments showed that the efficiency of the PB reaction was much higher when spraying the reagent solution than when sprinkling the reactant powder directly, and it was not lower than that in the liquid phase. This method can simplify the reaction conditions in the imaging process and can be applied to tissue section samples with only 10 min of pre-processing. The study successfully demonstrated the spatial distribution of unsaturated lipid isomers, and the isomeric ratio corresponded to the lesion areas in mouse brain cancer tissues. Due to its simple operation and performance in ambient conditions, this method may be useful for future studies on lipid isomers in tissues.


Assuntos
Lipídeos , Espectrometria de Massas por Ionização por Electrospray , Animais , Diagnóstico por Imagem , Isomerismo , Camundongos
4.
Zhongguo Zhong Yao Za Zhi ; 46(15): 3865-3872, 2021 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-34472261

RESUMO

Fifteen compounds(1-15) were isolated from the 95% EtOH extract of the whole herb of Physalis minima by various chromatography techniques including silica gel, Sephadex LH-20, middle chromatogram isolated gel(MCI), octadecyl silica(ODS), and semi-preparative high performance liquid chromatography(HPLC). Their structures were elucidated by infrared spectroscopy(IR), ultraviolet spectroscopy(UV), high-resolution electrospray ionization mass spectrometry(HR-ESI-MS), nuclear magnetic re-sonance(NMR), and circular dichroism(CD) as(5S)-5,11-dihydroxy-3-methyl-5-pentylfuran-2(5H)-one(1), withaphysalin R(2), withaphysalin Q(3), withaphysanolide A(4), phaseic acid(5), grasshopper ketone(6), 3S,5R-dihydroxy-6S,7-megastigmadien-9-one(7), vanillic acid(8), 2-trans,4-trans-abscisic acid(9), capillasterolide(10), 5,3'-dihydroxy-3,7,4'-trimethoxyflavone(11),(-)-loliolide(12), 4-hydroxyacetophenone(13), acetosyringone(14), and aurantiamide acetate(15). Compound 1 was a new butenolide, and compounds 5-7 and 10-12 were isolated from the Physalis for the first time. Compounds 4, 13, and 15 were isolated for the first time from P. minima. Moreover, their anti-inflammatory activity was evaluated in vitro. Compound 12 was found to possess an inhibitory effect on the transcription of an NF-κB-dependent reporter gene in LPS-induced 293 T/NF-κB-luc cells at 10 µmol·L~(-1), showing an inhibitory rate of 62.31%±4.8%.


Assuntos
Physalis , Anti-Inflamatórios , Cromatografia Líquida de Alta Pressão , NF-kappa B , Espectrometria de Massas por Ionização por Electrospray
5.
Molecules ; 26(15)2021 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-34361585

RESUMO

Bioactive molecules from the class of polyphenols are secondary metabolites from plants. They are present in honey from nectar and pollen of flowers from where honeybees collect the "raw material" to produce honey. Robinia pseudoacacia and Helianthus annuus are important sources of nectar for production of two monofloral honeys with specific characteristics and important biological activity. A high-performance liquid chromatography-electro spray ionization-mass spectrometry (HPLC-ESI-MS) separation method was used to determine polyphenolic profile from the two types of Romanian unifloral honeys. Robinia and Helianthus honey showed a common flavonoid profile, where pinobanksin (1.61 and 1.94 mg/kg), pinocembrin (0.97 and 1.78 mg/kg) and chrysin (0.96 and 1.08 mg/kg) were identified in both honey types; a characteristic flavonoid profile in which acacetin (1.20 mg/kg), specific only for Robinia honey, was shown; and quercetin (1.85 mg/kg), luteolin (21.03 mg/kg), kaempferol (0.96 mg/kg) and galangin (1.89 mg/kg), specific for Helianthus honey, were shown. In addition, different phenolic acids were found in Robinia and Helianthus honey, while abscisic acid was found only in Robinia honey. Abscisic acid was correlated with geographical location; the samples collected from the south part of Romania had higher amounts, due to climatic conditions. Acacetin was proposed as a biochemical marker for Romanian Robinia honey and quercetin for Helianthus honey.


Assuntos
Análise de Alimentos , Helianthus , Mel/análise , Polifenóis/análise , Robinia , Espectrometria de Massas por Ionização por Electrospray , Flavonas/análise , Quercetina/análise
6.
Anal Chem ; 93(32): 11321-11328, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34369157

RESUMO

In-source fragmentation-based high-resolution mass spectrometry (ISF-HRMS) is a potential analytical technique, which is usually used to profile some specific compounds that can generate diagnostic neutral loss (NL) or fragment ion (FI) in ion source inherently. However, the ISF-HRMS method does not work for those compounds that cannot inherently produce diagnostic NL or FI in ion source. In this study, a derivatization-based in-source fragmentation-information-dependent acquisition (DISF-IDA) strategy was proposed for profiling the metabolites with easily labeled functional groups (submetabolomes) by liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry (LC-ESI-Q-TOF MS). As a proof-of-concept study, 36 carboxylated compounds labeled with N,N-dimethylethylenediamine (DMED) were selected as model compounds to examine performance of DISF-IDA strategy in screening the carboxylated metabolites and acquiring their MSn spectra. In ESI source, the DEMD-derived carboxylated compounds were fragmented to produce characteristic neutral losses of 45.0578, 63.0684, and/or 88.1000 Da that were further used as diagnostic features for screening the carboxylated metabolites by DISF-IDA-based LC-Q-TOF MS. Furthermore, high-resolution MSn spectra of the model compounds were also obtained within a single run of DISF-IDA-based LC-Q-TOF MS analysis, which contributed to the improvement of the annotation confidence. To further verify its applicability, DISF-IDA strategy was used for profiling carboxylated submetabolome in mice feces. Using this strategy, a total of 351 carboxylated metabolites were detected from mice feces, of which 178 metabolites (51% of the total) were positively or putatively identified. Moreover, DISF-IDA strategy was also demonstrated to be applicable for profiling other submetabolomes with easily labeled functional groups such as amino, carbonyl, and cis-diol groups. Overall, our proposed DISF-IDA strategy is a promising technique for high-coverage profiling of submetabolomes with easily labeled functional groups in biological samples.


Assuntos
Ácidos Carboxílicos , Espectrometria de Massas por Ionização por Electrospray , Animais , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Camundongos
7.
Molecules ; 26(16)2021 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-34443314

RESUMO

Despite the common use of salens and hydroxyquinolines as therapeutic and bioactive agents, their metal complexes are still under development. Here, we report the synthesis of novel mixed-ligand metal complexes (MSQ) comprising salen (S), derived from (2,2'-{1,2-ethanediylbis[nitrilo(E) methylylidene]}diphenol, and 8-hydroxyquinoline (Q) with Co(II), Ni(II), Cd(II), Al(III), and La(III). The structures and properties of these MSQ metal complexes were investigated using molar conductivity, melting point, FTIR, 1H NMR, 13C NMR, UV-VIS, mass spectra, and thermal analysis. Quantum calculation, analytical, and experimental measurements seem to suggest the proposed structure of the compounds and its uncommon monobasic tridentate binding mode of salen via phenolic oxygen, azomethine group, and the NH group. The general molecular formula of MSQ metal complexes is [M(S)(Q)(H2O)] for M (II) = Co, Ni, and Cd or [M(S)(Q)(Cl)] and [M(S)(Q)(H2O)]Cl for M(III) = La and Al, respectively. Importantly, all prepared metal complexes were evaluated for their antimicrobial and anticancer activities. The metal complexes exhibited high cytotoxic potency against human breast cancer (MDA-MB231) and liver cancer (Hep-G2) cell lines. Among all MSQ metal complexes, CoSQ and LaSQ produced IC50 values (1.49 and 1.95 µM, respectively) that were comparable to that of cisplatin (1.55 µM) against Hep-G2 cells, whereas CdSQ and LaSQ had best potency against MDA-MB231 with IC50 values of 1.95 and 1.43 µM, respectively. Furthermore, the metal complexes exhibited significant antimicrobial activities against a wide spectrum of both Gram-positive and -negative bacterial and fungal strains. The antibacterial and antifungal efficacies for the MSQ metal complexes, the free S and Q ligands, and the standard drugs gentamycin and ketoconazole decreased in the order AlSQ > LaSQ > CdSQ > gentamycin > NiSQ > CoSQ > Q > S for antibacterial activity, and for antifungal activity followed the trend of LaSQ > AlSQ > CdSQ > ketoconazole > NiSQ > CoSQ > Q > S. Molecular docking studies were performed to investigate the binding of the synthesized compounds with breast cancer oxidoreductase (PDB ID: 3HB5). According to the data obtained, the most probable coordination geometry is octahedral for all the metal complexes. The molecular and electronic structures of the metal complexes were optimized theoretically, and their quantum chemical parameters were calculated. PXRD results for the Cd(II) and La(III) metal complexes indicated that they were crystalline in nature.


Assuntos
Antibacterianos/farmacologia , Complexos de Coordenação/síntese química , Complexos de Coordenação/farmacologia , Teoria da Densidade Funcional , Etilenodiaminas/síntese química , Simulação de Acoplamento Molecular , Oxiquinolina/síntese química , Oxiquinolina/farmacologia , Antibacterianos/química , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Complexos de Coordenação/química , Etilenodiaminas/química , Etilenodiaminas/farmacologia , Humanos , Concentração de Íons de Hidrogênio , Concentração Inibidora 50 , Ligantes , Testes de Sensibilidade Microbiana , Conformação Molecular , Oxiquinolina/química , Difração de Pó , Espectroscopia de Prótons por Ressonância Magnética , Espectrometria de Massas por Ionização por Electrospray , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria
8.
J Gen Virol ; 102(8)2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34424155

RESUMO

Infectious bronchitis virus (IBV) is an economically important coronavirus, causing damaging losses to the poultry industry worldwide as the causative agent of infectious bronchitis. The coronavirus spike (S) glycoprotein is a large type I membrane protein protruding from the surface of the virion, which facilitates attachment and entry into host cells. The IBV S protein is cleaved into two subunits, S1 and S2, the latter of which has been identified as a determinant of cellular tropism. Recent studies expressing coronavirus S proteins in mammalian and insect cells have identified a high level of glycosylation on the protein's surface. Here we used IBV propagated in embryonated hens' eggs to explore the glycan profile of viruses derived from infection in cells of the natural host, chickens. We identified multiple glycan types on the surface of the protein and found a strain-specific dependence on complex glycans for recognition of the S2 subunit by a monoclonal antibody in vitro, with no effect on viral replication following the chemical inhibition of complex glycosylation. Virus neutralization by monoclonal or polyclonal antibodies was not affected. Following analysis of predicted glycosylation sites for the S protein of four IBV strains, we confirmed glycosylation at 18 sites by mass spectrometry for the pathogenic laboratory strain M41-CK. Further characterization revealed heterogeneity among the glycans present at six of these sites, indicating a difference in the glycan profile of individual S proteins on the IBV virion. These results demonstrate a non-specific role for complex glycans in IBV replication, with an indication of an involvement in antibody recognition but not neutralisation.


Assuntos
Coronavirus/fisiologia , Polissacarídeos/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/metabolismo , Alcaloides/química , Alcaloides/farmacologia , Sequência de Aminoácidos , Animais , Sítios de Ligação , Células Cultivadas , Cromatografia Líquida , Biologia Computacional/métodos , Coronavirus/efeitos dos fármacos , Infecções por Coronavirus/veterinária , Regulação Viral da Expressão Gênica , Glicosilação/efeitos dos fármacos , Vírus da Bronquite Infecciosa/fisiologia , Modelos Moleculares , Conformação Molecular , Peso Molecular , Testes de Neutralização , Oligossacarídeos/química , Oligossacarídeos/metabolismo , Polissacarídeos/química , Doenças das Aves Domésticas/virologia , Transporte Proteico , Espectrometria de Massas por Ionização por Electrospray , Glicoproteína da Espícula de Coronavírus/genética , Relação Estrutura-Atividade , Replicação Viral/efeitos dos fármacos
9.
J Pharm Biomed Anal ; 204: 114279, 2021 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-34340019

RESUMO

Eight unknown impurities in xinfujunsu and its injection were characterized by liquid chromatography coupled with ion trap/time-of-flight mass spectrometry (LC-IT-TOF MS). In order to determine the m/z values of the molecular ions and predict the formulas of all detected impurities, full scan LC-MS in positive ion mode was firstly executed to obtain the m/z value of the molecules. Then LC-MS2, LC-MS3 and LC-MS4 were carried out on target compounds to obtain as much structural information as possible. Based on MSn spectral data and exact mass measurements, the chemical structures of eight unknown impurities were characterized, among which three impurities were degradation impurities and five impurities were process impurities. In addition, the source of impurities and the correlation between process and impurities were also studied. The production of degraded impurities was caused in the high pressure sterilization process of xinfujunsu injection. Based on characterization of impurities, this study revealed the cause of impurity production and provided guidance for enterprises to improve the process to reduce impurity content. Furthermore, this study also provided scientific basis for the further improvement of official monographs in pharmacopoeias.


Assuntos
Contaminação de Medicamentos , Espectrometria de Massas por Ionização por Electrospray , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Cromatografia Gasosa-Espectrometria de Massas , Injeções
10.
Anal Chim Acta ; 1176: 338767, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34399903

RESUMO

There are numerous examples of bioactive compounds containing carbonyl groups including modified proteins with oxidation of side chain of amino acid residues to aldehyde/ketone groups which are frequently considered as markers of oxidative stress. The carbonyl unit can be also distinguished as a substructure in many illegal drugs including anabolic steroids as well as cations derivatives. Based on chemoselective formation of oximes by solid phase immobilized hydroxylamine derivatives we proposed the protocol for derivatization and selective detection of carbonylated compounds in human serum albumin hydrolysate as a complex peptide mixture and of testosterone in urine samples. This allowed for the removal of the matrix and the qualitative and quantitative analysis of the derivatized analyte by LC-MS/MS (or LC-MRM). Herein we report the preparation and chemical characterization of a novel, ChemMatrix - based resin functionalized with aminooxyacetic acid (AOA). The hydroxylamine moiety in this resin is combined with a peptide linker (GRG) containing an arginine residue to enhance the ionization efficiency. Application of an isotopically labeled carbonylated peptide ((H-Leu-Val-Thr(O)-Asp-Leu-Thr-Lys [13C6,15N2]-OH and testosterone-d3 allowed us to carry out quantitative analyses of detected compounds. Our method is general and may be applied for analysis of carbonylated compounds in biological samples. Our method based on application of functionalized resin allowed to quantify the level of free testosterone in small sample (0.5 mL) of urine, while the non-derivatized testosterone from urine sample was not detected during direct LC-MRM analysis.


Assuntos
Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem , Ácido Amino-Oxiacético , Cromatografia Líquida , Humanos , Peptídeos
11.
Talanta ; 234: 122620, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34364429

RESUMO

We developed a methodology for rapid quantification of extracellular neurotransmitters in mouse brain by PESI/MS/MS and longitudinal data analysis using the R and Stan-based Bayesian state-space model. We performed a rapid analysis for quantifying extracellular l-glutamic acid (L-Glu) and gamma-aminobutyric acid (GABA) in the mouse striatum by combined use of probe electrospray ionization/tandem mass spectrometry (PESI/MS/MS) and in vivo brain microdialysis. We optimized the PESI/MS/MS parameters with the authentic L-Glu, GABA, L-Glu-13C5,15N1, and GABA-D6 standards. We constructed calibration curves of L-Glu and GABA with the stable isotope internal standard correction method (L-Glu-13C5,15N1, and GABA-D6), demonstrating sufficient linearity (R > 0.999). Additionally, the quantitative method for L-Glu and GABA was validated with low-, middle-, and high-quality control samples. The intra- and inter-day accuracy and precision were 0.4%-7.5% and 1.7%-5.4% for L-Glu, respectively, and 0.1%-4.8% and 2.1%-5.7% for GABA, respectively, demonstrating high reproducibility of the method. To evaluate the feasibility of this method, microdialyses were performed on free-moving mice that were stimulated by high-K+-induced depolarization under different sampling conditions: 1) every 5 min for 150 min (n = 2) and 2) every 1 min for 30 min (n = 3). We applied the R and Stan-based Bayesian state-space model to each mouse's time-series data considering autocorrelation, and the model successfully detected abnormal changes in the L-Glu and GABA levels in each mouse. Thus, the L-Glu and GABA levels in all microdialysates approximately increased up to two- and seven-fold levels through high-K+-induced depolarization. Additionally, a 1-min temporal resolution was achieved using this method, thereby successfully monitoring microenvironmental changes in the extracellular L-Glu and GABA of the mouse striatum. In conclusion, this methodology using PESI/MS/MS and Bayesian state-space model allowed easy monitoring of neurotransmitters at high temporal resolutions and appropriate data interpretation considering autocorrelation of time-series data, which will reveal hidden pathological mechanisms of brain diseases, such as Parkinson's disease and Huntington's disease in the future.


Assuntos
Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem , Animais , Teorema de Bayes , Encéfalo , Análise de Dados , Ácido Glutâmico , Camundongos , Microdiálise , Neurotransmissores , Reprodutibilidade dos Testes , Simulação de Ambiente Espacial
12.
Talanta ; 234: 122674, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34364474

RESUMO

Ambient ionization of glycans is simply and efficiently achieved by spraying from an alkali metal salt-impregnated paper surface. Monosaccharides, oligosaccharides and ring glycans easily form abundant alkali metal adduct ions, and give simple and clean high-quality mass spectra. The enhancement is specific for glycans, compared to a wide variety of non-glycan compounds present in a matrix. In addition, molecular weight of unknown glycans can be further identified based on the ion mass difference of various alkali metal adduct ions from a certain compound when using a mixed salt-impregnated paper containing five cation salts. Successful determination of glycans and glycoconjugates in plant extracts, honey, blood and urine demonstrates the practicability of this approach to complicated matrices, especially biological matrices.


Assuntos
Metais Alcalinos , Polissacarídeos , Peso Molecular , Oligossacarídeos , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
13.
Analyst ; 146(18): 5675-5681, 2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34388232

RESUMO

The wide application of nano-particles (NPs) has raised a serious concern over their impact on plants. However, evaluation of the effects of NPs on plant metabolism by direct detection of chemicals inside solid tissues presents a challenge. In this study, we report on a direct ionization method in mass spectrometry, internal extractive electrospray ionization (iEESI), for the direct evaluation of phytotoxicity of three different NPs (including CdTe quantum dots (CdTe QDs), gold nano-particles (Au NPs), and silver nano-particles (Ag NPs)) both on surfaces and inside solid tissues from the mung bean seeds (Vigna radiata) that were cultured in aqueous solutions of three NPs at 50 µg mL-1. The results showed that NPs could stimulate the biological accumulation of trigonelline and the decomposition of polysaccharides/oligosaccharides to glucose and maltose within 21 h of culture. To the best of our knowledge, this is the first study to apply internal extractive electrospray ionization mass spectrometry (iEESI-MS) for the direct measurement of solid tissue samples to evaluate the phytotoxicity of NPs on mung bean sprouts. Our study lays a solid foundation for further examination of other NPs-induced damaging effects such as apoptosis/necrosis, helping us to understand the phytotoxicity of NPs on plants.


Assuntos
Compostos de Cádmio , Pontos Quânticos , Vigna , Pontos Quânticos/toxicidade , Espectrometria de Massas por Ionização por Electrospray , Telúrio
14.
Analyst ; 146(18): 5682-5690, 2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34397059

RESUMO

A novel, convenient ambient electric arc ionization (AEAI) device was developed as a mass spectrometry ion source for versatile sample analysis. AEAI could be considered as a soft ionization technique in which the protonated ion ([M + H]+) is the main ion species with little or no in-source fragmentation for most analytes. Coupled with a high-resolution Orbitrap mass spectrometer, AEAI could be applied to the analysis of a variety of organic compounds having a wide range of polarities, ranging from non-polar species such as polybenzenoid aromatic hydrocarbons (PAHs) to highly polar species such as amino acids. With its versatile capabilities in the mass spectrometric analysis of small molecules, AEAI has the potential to be an alternative to traditional ionization methods such as electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), and electron impact (EI) ionization. The limitations of AEAI are also discussed.


Assuntos
Pressão Atmosférica , Compostos Orgânicos , Aminoácidos , Espectrometria de Massas , Espectrometria de Massas por Ionização por Electrospray
15.
Clin Immunol ; 230: 108825, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34403816

RESUMO

We have recently introduced multiple reaction monitoring (MRM) mass spectrometry as a novel tool for glycan biomarker research and discovery. Herein, we employ this technique to characterize the site-specific glycan alterations associated with primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC). Glycopeptides associated with disease severity were also identified. Multinomial regression modelling was employed to construct and validate multi-analyte diagnostic models capable of accurately distinguishing PBC, PSC, and healthy controls from one another (AUC = 0.93 ± 0.03). Finally, to investigate how disease-relevant environmental factors can influence glycosylation, we characterized the ability of bile acids known to be differentially expressed in PBC to alter glycosylation. We hypothesize that this could be a mechanism by which altered self-antigens are generated and become targets for immune attack. This work demonstrates the utility of the MRM method to identify diagnostic site-specific glycan classifiers capable of distinguishing even related autoimmune diseases from one another.


Assuntos
Autoimunidade , Colangite Esclerosante/imunologia , Cirrose Hepática Biliar/imunologia , Polissacarídeos/imunologia , Linfócitos B/imunologia , Linfócitos B/metabolismo , Ácidos e Sais Biliares/sangue , Ácidos e Sais Biliares/imunologia , Biomarcadores/sangue , Estudos de Casos e Controles , Colangite Esclerosante/sangue , Colangite Esclerosante/diagnóstico , Diagnóstico Diferencial , Glicômica/métodos , Glicopeptídeos/sangue , Glicopeptídeos/imunologia , Glicosilação , Humanos , Cirrose Hepática Biliar/sangue , Cirrose Hepática Biliar/diagnóstico , Polissacarídeos/sangue , Espectrometria de Massas por Ionização por Electrospray/métodos
16.
Int J Mol Sci ; 22(15)2021 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-34360905

RESUMO

Some Listeria species are important human and animal pathogens that can be found in contaminated food and produce a variety of virulence factors involved in their pathogenicity. Listeria strains exhibiting multidrug resistance are known to be progressively increasing and that is why continuous monitoring is needed. Effective therapy against pathogenic Listeria requires identification of the bacterial strain involved, as well as determining its virulence factors, such as antibiotic resistance and sensitivity. The present study describes the use of liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) to do a global shotgun proteomics characterization for pathogenic Listeria species. This method allowed the identification of a total of 2990 non-redundant peptides, representing 2727 proteins. Furthermore, 395 of the peptides correspond to proteins that play a direct role in Listeria pathogenicity; they were identified as virulence factors, toxins and anti-toxins, or associated with either antibiotics (involved in antibiotic-related compounds production or resistance) or resistance to toxic substances. The proteomic repository obtained here can be the base for further research into pathogenic Listeria species and facilitate the development of novel therapeutics for these pathogens.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/química , Farmacorresistência Bacteriana Múltipla , Listeria/efeitos dos fármacos , Listeria/patogenicidade , Proteoma/química , Fatores de Virulência/química , Transportadores de Cassetes de Ligação de ATP/química , Cromatografia Líquida/métodos , Genes Bacterianos , Listeria/classificação , Listeria/genética , Peptídeos/química , Proteômica/métodos , Espectrometria de Massas por Ionização por Electrospray/métodos , Espectrometria de Massas em Tandem/métodos
17.
Anal Chem ; 93(35): 12041-12048, 2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34431672

RESUMO

Because of its speed, sensitivity, and ability to scrutinize individual species, mass spectrometry (MS) has become an essential tool in analytical strategies aimed at studying the degradation behavior of polyesters. MS analyses can be performed prior to the degradation event for structural characterization of initial substrates or after it has occurred to measure the decreasing size of products as a function of time. Here, we show that MS can also be usefully employed during the degradation process by online monitoring the chain solvolysis induced by reactive desorption electrospray ionization (DESI). Cleavage of ester bonds in random copolymers of lactic acid (LA) and glycolic acid (GA) was achieved by electrospraying methanol-containing NaOH onto the substrates. Experimental conditions were optimized to generate methanolysis products of high abundance so that mass spectra can be conveniently processed using Kendrick-based approaches. The same reactive-DESI performance was demonstrated for two sample preparations, solvent casting for soluble samples or pressed pellets for highly crystalline substrates, permitting to compare polymers with LA/GA ratios ranging from 100/0 to 5/95. Analysis of sample fractions collected by size exclusion chromatography showed that methanolysis occurs independently of the original chain size, so data recorded for poly(LA-co-GA) (PLAGA) copolymers with the average molecular weight ranging from 10 to 180 kDa could be safely compared. The average mass of methanolysis products was observed to decrease linearly (R2 = 0.9900) as the GA content increases in PLAGA substrates, consistent with the susceptibility of ester bonds toward solvolysis being higher in GA than in LA. Because DESI only explores the surface of solids, these data do not reflect bulk degradability of the copolymers but, instead, their relative degradability at the molecular level. Based on a "reactive-DESI degradability scale" such as that established here for PLAGA, the proposed method offers interesting perspectives to qualify intrinsic degradability of different polyesters and evaluate their erosion susceptibility or to determine the degradability of those polymers known to degrade via erosion only.


Assuntos
Glicóis , Espectrometria de Massas por Ionização por Electrospray , Peso Molecular , Poliésteres , Copolímero de Ácido Poliláctico e Ácido Poliglicólico
18.
Anal Chem ; 93(36): 12204-12212, 2021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34461717

RESUMO

Diels-Alder chemistry is a well-explored avenue for the synthesis of bioactive materials; however, its potential applications have recently expanded following the development of reactions that can be performed in buffered aqueous environments at low temperatures, including fulvene-maleimide [4 + 2] cycloadditions. In this study, we synthesized two novel amine-reactive fulvene linkers to demonstrate the application of this chemistry for generating mass spectrometry-cleavable labels ("mass tags"), which can be used for the labeling and detection of proteins. Successful conjugation of these linkers to maleimide-labeled peptides was observed at low temperatures in phosphate-buffered saline, allowing the non-destructive modification of proteins with such mass tags. The labile nature of fulvene-maleimide adducts in the gas phase also makes them suitable for both matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) mass spectrometric analysis. Unlike previous examples of MALDI mass tags, we show that fulvene-maleimide cycloaddition adducts fragment predictably upon gas-phase activation without the need for bulky photocleavable groups. Further exploration of this chemistry could therefore lead to new approaches for mass spectrometry-based bioassays.


Assuntos
Peptídeos , Espectrometria de Massas por Ionização por Electrospray , Ciclopentanos , Maleimidas , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
19.
Anal Chem ; 93(33): 11576-11584, 2021 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-34378383

RESUMO

In this contribution, we report an efficient approach to multiplex electrospray ionization (ESI) sources for applications in analytical and preparative mass spectrometry. This is achieved using up to four orthogonal injection inlets implemented on the opposite sides of an electrodynamic ion funnel interface. We demonstrate that both the total ion current transmitted through the mass spectrometer and the signal-to-noise ratio increase by 3.8-fold using four inlets compared to one inlet. The performance of the new multiplexing approach was examined using different classes of analytes covering a broad range of mass and ionic charge. A deposition rate of >10 µg of mass-selected ions per day may be achieved by using the multiplexed sources coupled to preparative mass spectrometry. The almost proportional increase in the ion current with the number of ESI inlets observed experimentally is confirmed using gas flow and ion trajectory simulations. The simulations demonstrate a pronounced effect of gas dynamics on the ion trajectories in the ion funnel, indicating that the efficiency of multiplexing strongly depends on gas velocity field. The study presented herein opens up exciting opportunities for the development of bright ion sources, which will advance both analytical and preparative mass spectrometry applications.


Assuntos
Espectrometria de Massas por Ionização por Electrospray , Injeções , Íons
20.
Nutrients ; 13(7)2021 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-34371869

RESUMO

Hibiscus sabdariffa L. (H.s.) is a polyphenolic-rich plant commonly consumed either as a beverage or spice. The aim of the present study was to evaluate the in vitro digestibility of H.s. polyphenols using an in vitro model of digestion which simulates the human stomach and small intestine. The bioaccessible polyphenols released in the digested samples were analyzed by liquid chromatography coupled to photodiode array and mass spectrometry detection. H.s. anthocyanins (cyanidin-3-O-sambubioside and delphinidin-3-O-sambubioside) content drastically dropped during the digestion process from 2.91 ± 0.03 µg g-1 and 8.53 ± 0.08 µg g-1 (w/w) CG (Cyanidin-glucoside) in the raw extract, respectively, to 0.12 ± 0.01 µg g-1 0.12 ± 0.01 µg g-1 (w/w) CG at the end of duodenal digestion. Total polyphenols also have shown a decrease from 1192.65 ± 30.37 µg g-1 (w/w) in the raw extract to 282.24 ± 7.21 µg g-1 (w/w) by the end of gastric digestion, in contrast to their increase by the end of duodenal digestion 372.91 ± 3.97 µg g-1 (w/w). On the other hand, the decrease in certain compounds (e.g., caffeoylquinicandcoumaroylquinic acids) was observed during gastric digestion resulting in an increase of quinic acid in the duodenal aliquots, thus suggesting that this compound was derived from the degradation of the more complex hydroxycinnamic acids. H.s. extract also exhibited a bacteriostatic effect against Staphylococcus aureus ATCC 6538 (MIC of 2.5 mg mL-1) and a bactericidal effect against a food isolate of Listeria monocytogenes (MBC of 2.5 mg mL-1). The undigested polyphenols of H.s. in the upper gastrointestinal tract enters the colon, where they are metabolized by the gut microbiota. The present study results showed that resistance of H.s. polyphenols during gastrointestinal digestion might affect their uptake, resulting in a decrease in their digestibility.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Digestão , Hibiscus , Extratos Vegetais/farmacologia , Polifenóis/farmacologia , Antibacterianos/isolamento & purificação , Antibacterianos/metabolismo , Bactérias/crescimento & desenvolvimento , Disponibilidade Biológica , Cromatografia Líquida de Alta Pressão , Suco Gástrico/química , Hibiscus/química , Humanos , Secreções Intestinais/química , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/metabolismo , Polifenóis/isolamento & purificação , Polifenóis/metabolismo , Espectrometria de Massas por Ionização por Electrospray , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Espectrometria de Massas em Tandem
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