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1.
Sci Rep ; 11(1): 11119, 2021 05 27.
Artigo em Inglês | MEDLINE | ID: mdl-34045575

RESUMO

To analyse the cause of the atmospheric PM2.5 pollution that occurred during the COVID-19 lockdown in Nanning, Guangxi, China, a single particulate aerosol mass spectrometer, aethalometer, and particulate Lidar coupled with monitoring near-surface gaseous pollutants, meteorological conditions, remote fire spot sensing by satellite and backward trajectory models were utilized during 18-24 February 2020. Three haze stages were identified: the pre-pollution period (PPP), pollution accumulation period (PAP) and pollution dissipation period (PDP). The dominant source of PM2.5 in the PPP was biomass burning (BB) (40.4%), followed by secondary inorganic sources (28.1%) and motor vehicle exhaust (11.7%). The PAP was characterized by a large abundance of secondary inorganic sources, which contributed 56.1% of the total PM2.5 concentration, followed by BB (17.4%). The absorption Ångström exponent (2.2) in the PPP was higher than that in the other two periods. Analysis of fire spots monitored by remote satellite sensing indicated that open BB in regions around Nanning City could be one of the main factors. A planetary boundary layer-relative humidity-secondary particle matter-particulate matter positive feedback mechanism was employed to elucidate the atmospheric processes in this study. This study highlights the importance of understanding the role of BB, secondary inorganic sources and meteorology in air pollution formation and calls for policies for emission control strategies.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/análise , Monitoramento Ambiental/métodos , Gases/análise , Material Particulado/análise , Biomassa , COVID-19 , China , Poeira/análise , Monitoramento Ambiental/instrumentação , Poluição Ambiental/análise , Espectrometria de Massas/instrumentação , Meteorologia , Emissões de Veículos/análise
2.
Molecules ; 26(3)2021 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-33499348

RESUMO

Mass spectrometry-based molecular imaging has been utilized to map the spatial distribution of target metabolites in various matrixes. Among the diverse mass spectrometry techniques, matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) is the most popular for molecular imaging due to its powerful spatial resolution. This unparalleled high resolution, however, can paradoxically act as a bottleneck when the bio-imaging of large areas, such as a whole plant, is required. To address this issue and provide a more versatile tool for large scale bio-imaging, direct analysis in real-time-time of flight-mass spectrometry (DART-TOF-MS), an ambient ionization MS, was applied to whole plant bio-imaging of a medicinal plant, Ephedrae Herba. The whole aerial part of the plant was cut into 10-20 cm long pieces, and each part was further cut longitudinally to compare the contents of major ephedra alkaloids between the outer surface and inner part of the stem. Using optimized DART-TOF-MS conditions, molecular imaging of major ephedra alkaloids of the whole aerial part of a single plant was successfully achieved. The concentration of alkaloids analyzed in this study was found to be higher on the inner section than the outer surface of stems. Moreover, side branches, which are used in traditional medicine, represented a far higher concentration of alkaloids than the main stem. In terms of the spatial metabolic distribution, the contents of alkaloids gradually decreased towards the end of branch tips. In this study, a fast and simple macro-scale MS imaging of the whole plant was successfully developed using DART-TOF-MS. This application on the localization of secondary metabolites in whole plants can provide an area of new research using ambient ionization mass spectroscopy and an unprecedented macro-scale view of the biosynthesis and distribution of active components in medicinal plants.


Assuntos
Alcaloides/metabolismo , Ephedra/metabolismo , Espectrometria de Massas/métodos , Plantas Medicinais/metabolismo , Efedrina/análogos & derivados , Efedrina/metabolismo , Espectrometria de Massas/instrumentação , Imagem Molecular/instrumentação , Imagem Molecular/métodos , Componentes Aéreos da Planta/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
3.
Anal Bioanal Chem ; 413(4): 1099-1106, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33388931

RESUMO

We develop a capillary-paper spray (CPS) ion source which allows for sample separation in the capillary and enables rapid and sensitive paper spray (PS) mass spectrometry (MS) analysis of biofluids. The CPS employs a glass capillary to load liquid analytes, vertically standing at the rear of the PS. To further reduce the matrix effect, a nitrocellulose filter membrane is placed between the glass tube and chromatography paper to absorb proteins and other macromolecules, which is beneficial for the detection of the small molecules. Compared with the normal PS method, the CPS method markedly improves spray stability and prolongs analysis duration, and also generates significantly better signal intensities during the analysis of drugs, thus indicating its potential for clinical use. As a proof of concept, quantitative analysis of drugs (metformin hydrochloride and berberine hydrochloride) in serum is performed.


Assuntos
Berberina/análise , Hipoglicemiantes/análise , Espectrometria de Massas/instrumentação , Metformina/análise , Animais , Berberina/sangue , Bovinos , Desenho de Equipamento , Hipoglicemiantes/sangue , Metformina/sangue , Papel , Soro/química
4.
Nature ; 589(7843): 630-632, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33500572

Assuntos
Anticorpos/uso terapêutico , Vacinas contra COVID-19 , Biologia Celular , Biologia do Desenvolvimento , Nariz Eletrônico , Espectrometria de Massas/instrumentação , Neurociências , Animais , Anticorpos/química , Anticorpos/genética , Anticorpos/imunologia , Proteínas de Bactérias/efeitos dos fármacos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/efeitos da radiação , Bioimpressão/tendências , COVID-19/epidemiologia , COVID-19/imunologia , COVID-19/prevenção & controle , Vacinas contra COVID-19/química , Vacinas contra COVID-19/imunologia , Vacinas contra COVID-19/provisão & distribuição , Biologia Celular/instrumentação , Biologia Celular/tendências , Biologia do Desenvolvimento/métodos , Biologia do Desenvolvimento/tendências , Embrião de Mamíferos/citologia , Embrião de Mamíferos/embriologia , Embrião de Mamíferos/metabolismo , Desenvolvimento Embrionário/genética , Holografia/tendências , Humanos , Imunoglobulina E/química , Imunoglobulina E/genética , Imunoglobulina E/imunologia , Imunoglobulina E/uso terapêutico , Canais Iônicos/metabolismo , Espectrometria de Massas/métodos , Proteínas de Membrana/efeitos dos fármacos , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Proteínas de Membrana/efeitos da radiação , Camundongos , Microscopia/instrumentação , Microscopia/tendências , Sondas Moleculares/análise , Neoplasias/tratamento farmacológico , Neurociências/métodos , Neurociências/tendências , Optogenética/tendências , Análise de Célula Única , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
5.
JCI Insight ; 6(3)2021 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-33351780

RESUMO

Recent in vivo tracer studies demonstrated that targeted mass spectrometry (MS) on the Q Exactive Orbitrap could determine the metabolism of HDL proteins 100s-fold less abundant than apolipoprotein A1 (APOA1). In this study, we demonstrate that the Orbitrap Lumos can measure tracer in proteins whose abundances are 1000s-fold less than APOA1, specifically the lipid transfer proteins phospholipid transfer protein (PLTP), cholesterol ester transfer protein (CETP), and lecithin-cholesterol acyl transferase (LCAT). Relative to the Q Exactive, the Lumos improved tracer detection by reducing tracer enrichment compression, thereby providing consistent enrichment data across multiple HDL sizes from 6 participants. We determined by compartmental modeling that PLTP is secreted in medium and large HDL (alpha2, alpha1, and alpha0) and is transferred from medium to larger sizes during circulation from where it is catabolized. CETP is secreted mainly in alpha1 and alpha2 and remains in these sizes during circulation. LCAT is secreted mainly in medium and small HDL (alpha2, alpha3, prebeta). Unlike PLTP and CETP, LCAT's appearance on HDL is markedly delayed, indicating that LCAT may reside for a time outside of systemic circulation before attaching to HDL in plasma. The determination of these lipid transfer proteins' unique metabolic structures was possible due to advances in MS technologies.


Assuntos
Proteínas de Transferência de Ésteres de Colesterol/sangue , Lipoproteínas HDL/sangue , Espectrometria de Massas/métodos , Fosfatidilcolina-Esterol O-Aciltransferase/sangue , Proteínas de Transferência de Fosfolipídeos/sangue , Análise Química do Sangue/instrumentação , Análise Química do Sangue/métodos , Deutério/análise , Deutério/sangue , Feminino , Humanos , Cinética , Lipoproteínas HDL/química , Masculino , Espectrometria de Massas/instrumentação , Modelos Biológicos , Peso Molecular , Tamanho da Partícula
6.
Methods Mol Biol ; 2237: 55-67, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33237408

RESUMO

The coupling of surface plasmon resonance imaging (SPRi) with mass spectrometry (MS) offers a very promising multidimensional analysis. This system takes advantage of the two well-established techniques: SPR, which allows for the analysis of biomolecular interactions through the determination of kinetic and thermodynamic constants, and MS, which can characterize biological structures from mass measurements and fragmentation experiments. Here, a protocol for the coupling of SPRi with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is described using a biochip grafted by antibodies in an array format. Interaction between ß-lactoglobulin antibodies and the protein antigen is detected and analyzed by SPRi. Then, the arrayed biochip which fitted a commercially MALDI target was inserted in a MALDI source, and mass spectra were recorded directly from the biochip surface from each antibody spot, showing protein ions attributed to the corresponding specific protein antigens.


Assuntos
Antígenos/análise , Espectrometria de Massas/métodos , Análise Serial de Proteínas/métodos , Ressonância de Plasmônio de Superfície/métodos , Antígenos/imunologia , Imunoensaio/instrumentação , Imunoensaio/métodos , Dispositivos Lab-On-A-Chip , Espectrometria de Massas/instrumentação , Análise Serial de Proteínas/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação
7.
Methods Mol Biol ; 2130: 19-27, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33284433

RESUMO

Inductively coupled plasma mass spectrometry (ICP-MS) is a sensitive instrumental analysis technique used for multielemental and isotopic determination. Here we provide a sample preparation and circadian ICP-MS analysis protocol for use with mammalian tissues and cells, using mouse fibroblasts as a case study.


Assuntos
Relógios Circadianos , Espectrometria de Massas/métodos , Animais , Células Cultivadas , Fibroblastos/metabolismo , Espectrometria de Massas/instrumentação , Camundongos
8.
Nat Commun ; 11(1): 3781, 2020 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-32728047

RESUMO

Nanomechanical mass spectrometry has proven to be well suited for the analysis of high mass species such as viruses. Still, the use of one-dimensional devices such as vibrating beams forces a trade-off between analysis time and mass resolution. Complex readout schemes are also required to simultaneously monitor multiple resonance modes, which degrades resolution. These issues restrict nanomechanical MS to specific species. We demonstrate here single-particle mass spectrometry with nano-optomechanical resonators fabricated with a Very Large Scale Integration process. The unique motion sensitivity of optomechanics allows designs that are impervious to particle position, stiffness or shape, opening the way to the analysis of large aspect ratio biological objects of great significance such as viruses with a tail or fibrils. Compared to top-down beam resonators with electrical read-out and state-of-the-art mass resolution, we show a three-fold improvement in capture area with no resolution degradation, despite the use of a single resonance mode.


Assuntos
Espectrometria de Massas/métodos , Nanotecnologia/métodos , Dispositivos Ópticos , Imagem Individual de Molécula/métodos , Amiloide/química , Desenho de Equipamento , Espectrometria de Massas/instrumentação , Nanopartículas/química , Nanotecnologia/instrumentação , Imagem Individual de Molécula/instrumentação , Vírus/química
9.
Nat Commun ; 11(1): 3019, 2020 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-32541649

RESUMO

Transcription factors (TFs) regulate target genes by specific interactions with DNA sequences. Detecting and understanding these interactions at the molecular level is of fundamental importance in biological and clinical contexts. Crosslinking mass spectrometry is a powerful tool to assist the structure prediction of protein complexes but has been limited to the study of protein-protein and protein-RNA interactions. Here, we present a femtosecond laser-induced crosslinking mass spectrometry (fliX-MS) workflow, which allows the mapping of protein-DNA contacts at single nucleotide and up to single amino acid resolution. Applied to recombinant histone octamers, NF1, and TBP in complex with DNA, our method is highly specific for the mapping of DNA binding domains. Identified crosslinks are in close agreement with previous biochemical data on DNA binding and mostly fit known complex structures. Applying fliX-MS to cells identifies several bona fide crosslinks on DNA binding domains, paving the way for future large scale ex vivo experiments.


Assuntos
DNA/química , Espectrometria de Massas/métodos , Fatores de Transcrição NFI/química , Proteína de Ligação a TATA-Box/química , Fatores de Transcrição/química , Animais , DNA/genética , DNA/metabolismo , Humanos , Lasers , Espectrometria de Massas/instrumentação , Fatores de Transcrição NFI/genética , Fatores de Transcrição NFI/metabolismo , Ligação Proteica , Domínios Proteicos , Suínos , Proteína de Ligação a TATA-Box/genética , Proteína de Ligação a TATA-Box/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
10.
Proc Natl Acad Sci U S A ; 117(13): 7338-7346, 2020 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-32179675

RESUMO

Clearance of surgical margins in cervical cancer prevents the need for adjuvant chemoradiation and allows fertility preservation. In this study, we determined the capacity of the rapid evaporative ionization mass spectrometry (REIMS), also known as intelligent knife (iKnife), to discriminate between healthy, preinvasive, and invasive cervical tissue. Cervical tissue samples were collected from women with healthy, human papilloma virus (HPV) ± cervical intraepithelial neoplasia (CIN), or cervical cancer. A handheld diathermy device generated surgical aerosol, which was transferred into a mass spectrometer for subsequent chemical analysis. Combination of principal component and linear discriminant analysis and least absolute shrinkage and selection operator was employed to study the spectral differences between groups. Significance of discriminatory m/z features was tested using univariate statistics and tandem MS performed to elucidate the structure of the significant peaks allowing separation of the two classes. We analyzed 87 samples (normal = 16, HPV ± CIN = 50, cancer = 21 patients). The iKnife discriminated with 100% accuracy normal (100%) vs. HPV ± CIN (100%) vs. cancer (100%) when compared to histology as the gold standard. When comparing normal vs. cancer samples, the accuracy was 100% with a sensitivity of 100% (95% CI 83.9 to 100) and specificity 100% (79.4 to 100). Univariate analysis revealed significant MS peaks in the cancer-to-normal separation belonging to various classes of complex lipids. The iKnife discriminates healthy from premalignant and invasive cervical lesions with high accuracy and can improve oncological outcomes and fertility preservation of women treated surgically for cervical cancer. Larger in vivo research cohorts are required to validate these findings.


Assuntos
Espectrometria de Massas/instrumentação , Espectrometria de Massas/métodos , Neoplasias do Colo do Útero/patologia , Adulto , Idoso , Neoplasia Intraepitelial Cervical , Análise Discriminante , Feminino , Cromatografia Gasosa-Espectrometria de Massas/instrumentação , Cromatografia Gasosa-Espectrometria de Massas/métodos , Humanos , Margens de Excisão , Pessoa de Meia-Idade , Papillomaviridae , Infecções por Papillomavirus/patologia , Lesões Pré-Cancerosas/diagnóstico , Lesões Pré-Cancerosas/cirurgia , Sensibilidade e Especificidade , Neoplasias do Colo do Útero/diagnóstico , Neoplasias do Colo do Útero/cirurgia
11.
Anal Bioanal Chem ; 412(10): 2315-2326, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32198533

RESUMO

The intestinal microbiome plays an important role in human health and disease and fecal materials reflect the microbial activity. Thus, analysis of fecal metabolites provides insight in metabolic interactions between gut microbiota and host organism. In this work, we applied flow injection analysis coupled to Fourier transform mass spectrometry (FIA-FTMS) to identify and quantify lipid species in human fecal samples. Fecal homogenates were subjected to lipid extraction and analyzed by FIA-FTMS. The analysis of different subjects revealed a vast heterogeneity of lipid species abundance. The majority of samples displayed prominent signals of triacylglycerol (TG) and diacylglycerol (DG) species that could be verified by MS2 spectra. Therefore, we focused on the quantification of TG and DG. Method validation included limit of quantification, linearity, evaluation of matrix effects, recovery, and reproducibility. The validation experiments demonstrated the suitability of the method, with exception for approximately 10% of samples, where we observed coefficients of variation higher than 15%. Impaired reproducibility was related to sample inhomogeneity and could not be improved by additional sample preparation steps. Additionally, these experiments demonstrated that compared with aqueous samples, samples containing isopropanol showed higher amounts of DG, presumably due to lysis of bacteria and increased TG lipolysis. These effects were sample-specific and substantiate the high heterogeneity of fecal materials as well as the need for further evaluation of pre-analytic conditions. In summary, FIA-FTMS offers a fast and accurate tool to quantify DG and TG species and is suitable to provide insight into the fecal lipidome and its role in health and disease.


Assuntos
Diglicerídeos/química , Fezes/química , Análise de Injeção de Fluxo/métodos , Espectrometria de Massas/métodos , Triglicerídeos/química , Humanos , Espectrometria de Massas/instrumentação
12.
J Am Soc Mass Spectrom ; 31(2): 418-428, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-32031393

RESUMO

Mass spectrometry (MS) has emerged as a valuable technology for molecular and spatial evaluation of biological samples. Ambient ionization MS techniques, in particular, allow direct analysis of tissue samples with minimal pretreatment. Here, we describe the design and optimization of an alternative ambient liquid extraction MS approach for metabolite and lipid profiling and imaging from biological samples. The system combines a piezoelectric picoliter dispenser to form solvent nanodroplets onto the sample surface with controlled and tunable spatial resolution and a conductive capillary to directly aspirate/ionize the nanodroplets for efficient analyte transmission and detection. Using this approach, we performed spatial profiling of mouse brain tissue sections with different droplet sizes (390, 420, and 500 µm). MS analysis of normal and cancerous human brain and ovarian tissues yielded rich metabolic profiles that were characteristic of disease state and enabled visualization of tissue regions with different histologic composition. This method was also used to analyze the lipid profiles of human ovarian cell lines. Overall, our results demonstrate the capabilities of this system for spatially controlled MS analysis of biological samples.


Assuntos
Química Encefálica , Lipídeos/análise , Espectrometria de Massas/instrumentação , Neoplasias Ovarianas/química , Ovário/química , Animais , Desenho de Equipamento , Feminino , Humanos , Espectrometria de Massas/métodos , Metaboloma , Camundongos , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia , Ovário/metabolismo , Ovário/patologia
13.
J Am Soc Mass Spectrom ; 31(2): 458-462, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-32031394

RESUMO

The development of native mass spectrometry (MS) has provided structural biologists an additional tool to probe the structures of large macromolecular systems. Surface-induced dissociation (SID) is one activation method used within tandem MS experiments that has proven useful in interrogating the connectivity and topology of biologically-relevant protein complexes. We present here the use of a tilted surface and ion carpet array within a new SID device design, enabling decreased dimensions along the ion path and fewer lenses to tune. This device works well in fragmenting ions of both low (peptides) and high (protein complexes) m/z. Results show that the ion carpet array, while enabling simplification of the back-end of the device, has deficiencies in product collection and subsequently signal at higher SID energies when fragmenting protein complexes. However, the use of the tilted surface is advantageous as an effective way to shorten the device and reduce the number of independent voltages.


Assuntos
Espectrometria de Massas/instrumentação , Peptídeos/química , Encefalina Leucina/química , Desenho de Equipamento , Íons/análise , Proteínas/química , Propriedades de Superfície
14.
Food Chem ; 317: 126455, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32109659

RESUMO

This study presents an experimental approach to study the kinetics and fast release of volatile organic compounds (VOCs) upon reconstitution of instant coffee products. A sampling setup coupled to PTR-ToF-MS (Proton Transfer Reaction Time-of-Flight Mass Spectrometry) for the automated and reproducible reconstitution of instant coffee products was developed to monitor the dynamic release of VOCs. A rapid release of aroma compounds was observed in the first seconds upon hot water addition ("aroma burst"), followed by subsequent decrease in headspace (HS) intensities over the course of analysis. Differences in time-intensity release profiles of individual VOCs were correlated to their Henry's Law constant, vapor pressure and water solubility. The setup and approach proposed here have shown to be sensitive and to respond to fast dynamic changes in aroma release. It allows studying VOCs release upon reconstitution and supports the development of novel technologies and formulations for instant products with improved aroma release properties.


Assuntos
Café/química , Análise de Alimentos/métodos , Odorantes/análise , Compostos Orgânicos Voláteis/análise , Análise de Alimentos/instrumentação , Cinética , Espectrometria de Massas/instrumentação , Espectrometria de Massas/métodos , Prótons , Solubilidade , Água
15.
Analyst ; 145(4): 1129-1157, 2020 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-31971527

RESUMO

Liquid chromatography (LC) based techniques in combination with mass spectrometry (MS) detection have had a large impact on the development of new pharmaceuticals in the past decades. Continuous improvements in mass spectrometry and interface technologies, combined with advanced liquid chromatographic techniques for high-throughput qualitative and quantitative analysis, have resulted in a wider scope of applications in the pharmaceutical field. LC-MS tools are increasingly used to analyze pharmaceuticals across a variety of stages in their discovery and development. These stages include drug discovery, product characterization, metabolism studies (in vitro and in vivo) and the identification of impurities and degradation products. The increase in LC-MS applications has been enormous, with retention times and molecular weights (and related fragmentation patterns) emerging as crucial analytical features in the drug development process. The goal of this review is to give an overview of the main developments in LC-MS based techniques for the analysis of small pharmaceutical molecules in the last decade and give a perspective on future trends in LC-MS in the pharmaceutical field.


Assuntos
Cromatografia Líquida/métodos , Desenvolvimento de Medicamentos/instrumentação , Descoberta de Drogas/instrumentação , Espectrometria de Massas/métodos , Animais , Cromatografia Líquida/instrumentação , Contaminação de Medicamentos , Desenho de Equipamento , Ensaios de Triagem em Larga Escala/métodos , Humanos , Espectrometria de Massas/instrumentação , Microfluídica/instrumentação , Microfluídica/métodos , Preparações Farmacêuticas/análise , Preparações Farmacêuticas/química , Preparações Farmacêuticas/metabolismo
16.
J Agric Food Chem ; 68(7): 2240-2248, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-31975589

RESUMO

An electric soldering iron ion source (ESII) coupling with rapid evaporative ionization mass spectrometry (REIMS) was developed and used for in situ monitoring the dynamic variation trend in oxidation characteristics of fish oil during storage. The lipidomics profiles of fish oil stored at various days were acquired by ESII-REIMS. The fatty acid and triacylglycerol species were structurally identified, and their abundances were analyzed according to multivariate statistical models mainly including principle component analysis as well as orthogonal partial least-squares analysis. On the shared and unique structure plot, the ions of m/z 255.23, 281.24, 877.72, and 901.72 displayed the most significant variation among the oxidized fish oil samples. Based on receiver operating characteristic curve analysis with an optimal Youden index of 0.91, these markers were further verified. The variation of viscosity and volatiles were also evaluated to further verify the oxidation characteristics of fish oil. The study demonstrated that ESII-REIMS technology used as an advanced detection method could ensure fish oil quality during storage.


Assuntos
Óleos de Peixe/química , Lipidômica/métodos , Espectrometria de Massas/métodos , Ácidos Graxos/química , Armazenamento de Alimentos , Espectrometria de Massas/instrumentação , Oxirredução , Triglicerídeos/química , Viscosidade
17.
Anal Chim Acta ; 1098: 27-36, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31948584

RESUMO

Biomedical analytical methods often rely on indirect measurements, such as immunoassays, which can lack effective metrological traceability. In the nephelometric determination of ceruloplasmin (Cp), an important protein whose circulating level is altered in Wilson's disease (WD), the anti-Cp antibody used is not specific for the biologically active holoprotein so the assay can overestimate the concentration of Cp due to the presence of the apoprotein. By providing quantitation using elemental standards, the use of strong anion exchange chromatography (SAX) coupled to triple quadrupole inductively coupled plasma mass spectrometry (ICP-MS-MS) can overcome the drawbacks of methods for the measurement of metalloproteins reliant on immunoassays. In the current study, a SAX-ICP-MS-MS method for Cp quantification was designed and tested in samples of blood serum of WD patients and healthy controls. Using standards based on a copper-EDTA complex for calibration, the method provides relatively simple quantification of Cp with the limit of detection of 0.1 µg L-1 (limit of quantification 0.4 µg L-1). The method was also used to investigate the copper species separated by using a 30 kDa cut-off ultrafiltration device. The so-called "exchangeable" copper fraction is considered as an alternative clinical biomarker of WD. Using the designed speciation approach, it was shown that the ultrafiltration method can overestimate the "exchangeable" copper fraction due to a removal of copper from Cp. This was confirmed by comparing the enzymatic activity of the fractions. Thus, the specificity of the "exchangeable" copper test can be ensured only under strict maintenance of ultrafiltration conditions.


Assuntos
Pesquisa Biomédica , Cobre/sangue , Degeneração Hepatolenticular/sangue , Cromatografia por Troca Iônica/instrumentação , Degeneração Hepatolenticular/diagnóstico , Humanos , Espectrometria de Massas/instrumentação
18.
Talanta ; 208: 120381, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31816699

RESUMO

Amino acids have been of great interest in clinical studies since variation in their concentration may provide information about different disorders. For the first time, a non-separative method based on single quadrupole mass spectrometry (qMS) for the simultaneous semiquantitative determination of sixteen amino acids in saliva samples has been developed. The method includes derivatisation of amino acids with ethyl chloroformate-pyridine-ethanol to obtain volatile products, liquid-liquid extraction (LLE) and further analysis using a programmed temperature vaporizer (PTV) coupled to qMS. This method could be applied to the analysis of a great number of saliva samples, limiting the use of separative methods only when abnormal concentrations of amino acids were found, reducing analysis time and cost. The results obtained in the determination of amino acids using the non-separative method were compared to those obtained when a separative method based on gas chromatography (GC) was used, providing values of average relative predictive error (E %) ranging between 2 and 48%. Repeatability and reproducibility were tested, obtaining relative standard deviation (RSD) values equal to or lower than 11% and 16%, respectively. Detection limits were in the range of 0.076-8.747 mg L-1 for the non-separative method.


Assuntos
Aminoácidos/análise , Espectrometria de Massas/instrumentação , Saliva/química , Aminoácidos/química , Calibragem , Humanos , Temperatura
19.
J Chromatogr A ; 1611: 460575, 2020 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-31607445

RESUMO

Improvements in sample preparation, separation, and mass spectrometry continue to expand the coverage in LC-MS based lipidomics. While longer columns packed with smaller particles in theory give higher separation performance compared to shorter columns, the implementation of this technology above commercial limits has been sparse due to difficulties in packing long columns and successfully operating instruments at ultrahigh pressures. In this work, a liquid chromatograph that operates up to 35 kpsi was investigated for the separation and identification of lipid species from human plasma. Capillary columns between 15-50 cm long were packed with 1.7 µm BEH C18 particles and evaluated for their ability to separate lipid isomers and complex lipid extracts from human plasma. Putative lipid class identifications were assigned using accurate mass and relative retention time data of the eluting peaks. Our findings indicate that longer columns packed and operated at 35 kpsi outperform shorter columns packed and run at lower pressures in terms of peak capacity and numbers of features identified. Packing columns with relatively high concentration slurries (200 mg/mL) while sonicating the column resulted in 6-34% increase in peak capacity for 50 cm columns compared to lower slurry concentrations and no sonication. For a given analysis time, 50 cm long columns operated at 35 kpsi provided a 20-95% increase in chromatographic peak capacity compared with 15 cm columns operated at 15 kpsi. Analysis times up to 4 h were evaluated, generating peak capacities up to 410 ±â€¯5 (n = 3, measured at 4σ) and identifying 480 ±â€¯85 lipids (n = 2). Importantly, the results also show a correlation between the peak capacity and the number of lipids identified from a human plasma extract. This correlation indicates that ionization suppression is a limiting factor in obtaining sufficient signal for identification by mass spectrometry. The result also shows that the higher resolution obtained by shallow gradients overcomes possible signal reduction due to broader, more dilute peaks in long gradients for improving detection of lipids in LC-MS. Lastly, longer columns operated at shallow gradients allowed for the best separation of both regional and geometrical isomers. These results demonstrate a system that enables the advantages of using longer columns packed and run at ultrahigh pressure for improving lipid separations and lipidome coverage.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Lipidômica/métodos , Lipídeos/química , Espectrometria de Massas/métodos , Cromatografia Líquida de Alta Pressão/instrumentação , Humanos , Lipidômica/instrumentação , Lipídeos/sangue , Espectrometria de Massas/instrumentação , Sonicação
20.
Talanta ; 206: 120174, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514890

RESUMO

A method of simultaneous cell counting and determination of metals in single cells using time-resolved inductively coupled plasma-mass spectrometry (ICP-MS) was reported. A facile, low cost and highly efficient single-cell introduction system of time-resolved ICP-MS consists of a flow cell, a visual contrast calibration device, a customized nebulizer and a fabricated spray chamber. The flow cell includes a cell sample tube, a sheath liquid tube and a flow chamber. The visual contrast calibration device was composed of a microscope with a 16 × microscope objective (160 × total magnification). The flow chamber was used to combine a flow of red blood cell suspension (0.800 µL/min) and a flow of PBS (4.40 µL/min) into the nebulizer. The intact cells were directly introduced with the single-cell introduction system into the plasma via nebulizing, and then ion plumes corresponding to single cells were individually detected with mass spectrometer. The frequency of the spikes directly reflects the number of cells, and the intensity of spikes is proportional to the concentration of copper within one cell. The single-cell introduction system can be transported into the ICP-MS via a customized transport system with 100% efficiency. A high cell introduction efficiency into the plasma supports for a reduction of cell consumption. The Cu signal frequency was about 120 cell events per minute. This single-cell introduction system simplifies the introduction of individual and intact cells. The copper content in single red blood cell was 0.20-0.40 fg.


Assuntos
Cobre/análise , Eritrócitos/química , Humanos , Limite de Detecção , Espectrometria de Massas/instrumentação , Espectrometria de Massas/métodos , Nebulizadores e Vaporizadores , Análise de Célula Única/instrumentação , Análise de Célula Única/métodos
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