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1.
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
2.
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
3.
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
4.
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
5.
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
6.
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
7.
J Chromatogr A ; 1616: 460779, 2020 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-31866135

RESUMO

Natural products, including alkaloids, are important resources for new drugs. However, in today's high throughput screening (HTS) environment, natural product drug discovery programs are challenged for their low efficiency. In order to adapt to current HTS models, we here developed a rapid, sample-saving and miniaturized paradigm that seamlessly integrated alkaloid micro-fractionation, quantitative analysis, qualitative analysis and phenotypic screening. In the work, alkaloid samples were analyzed and fractionated on an analytical charged C18 column (150 × 4.6 mm, i.d.), and fraction qualities were determined by a charged aerosol detector (CAD). Fraction activities on dopamine D2 receptor were screened by cellular dynamic mass redistribution (DMR) assay and active fractions were further characterized by high-resolution mass spectrometry (MS). The whole workflow was first validated by mixed standard for accuracy, and then by 300 µg of Corydalis yanhusuo extract for its feasibility in complex samples. Finally, the method was applied for sample prioritization in four papaveraceae family plants and 21 compounds were predicted to be active, and Corydalis yanhusuo and Corydalis decumbens were determined as promising species for activity tracking. Overall, these results highlighted the feasibility of this miniatured and integrated model in rapid alkaloid screening. Advantages of this workflow were: first, the highly efficient separation method accelerated alkaloid fractionation; second, the analytical and biological test were conducted on the same scale; third, the quantification method ensured accurate screening on microscale; last, the combination of MS analysis and data mining strategy accelerated the decision-making process in the primary screening.


Assuntos
Alcaloides/análise , Fracionamento Químico , Cromatografia Líquida de Alta Pressão , Descoberta de Drogas/instrumentação , Descoberta de Drogas/métodos , Espectrometria de Massas , Extratos Vegetais , Bioensaio , Corydalis/química , Espectrometria de Massas/instrumentação , Extratos Vegetais/química
8.
J Fluoresc ; 29(6): 1445-1455, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31768708

RESUMO

Phenylalanine (Phe) is a direct precursor of tyrosine and several neurotransmitters. The accumulation of Phe in the brain generates serious and not recoverable pathologies in children. Early detection in newborns is fundamental to apply the appropriate therapy and avoid irreversible health problems. Although fluorescence is a sensitive and selective technique for the determination of amino acids, the fluorescent analysis of Phe is limited since it exhibits a very low fluorescence quantum yield; however, the fluorescence of Phe increases drastically under UV irradiation when a peroxide medium is used. The aim of this research was to analyze the effect of the UV-radiation on Phe aqueous-peroxide solutions and to study the influence of the chemical environment on the photoinducted fluorescence process. The nature and characteristics of the fluorescent photoproducts generated under off-line UV irradiation in hydrogen peroxide medium were achieved by high performance liquid chromatography (HPLC) using a spectrophotometer detector (DAD) coupled in series with a mass spectrometer (MS) or with a fast scan spectrofluorimetric detector (FSFD). Environmental characteristics such as pH, initial concentration of Phe, hydrogen peroxide amount and irradiation time were studied in order to establish their influence on the formation of each one of the photoproducts. As the formation of several highly fluorescent photoproducts has been confirmed, the possibility of designing a chromatographic system with a post-column on-line photoreactor is open. The measure of the total fluorescence signal generated from Phe at the optimized irradiation time, could be used for the determination, with high sensitivity, of the initial amount of Phe in aqueous media, such as human serum or environmental samples. These aspects are being studied at present. .


Assuntos
Fluorescência , Corantes Fluorescentes/química , Fenilalanina/química , Cromatografia Líquida de Alta Pressão/instrumentação , Peróxido de Hidrogênio/química , Espectrometria de Massas/instrumentação , Processos Fotoquímicos , Software , Raios Ultravioleta
9.
Anal Chim Acta ; 1089: 56-65, 2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31627819

RESUMO

A novel all-in-one paper-based sampling concept for mass spectrometric bottom-up protein analysis is here demonstrated in a chip format integrating instant immunocapture, protein reduction, - alkylation and tryptic digestion all in-device. Conventional laboratory grade filter paper was coated with the polymer 2-hydroxyethyl methacrylate-co-2-vinyl-4,4-dimethyl azlactone (pHEMA-VDM) with a subsequent covalent immobilization of the monoclonal antibody E27 targeting the biomarker human chorionic gonadotropin (hCG). In-device protein reduction and alkylation was optimized with regards to reagent concentration and reaction pH. The sampling concept showed a high degree of performance between 10 and 1000 ng/mL (R2 > 0.99) by a five-point calibration curve sampled with hCG spiked to human serum samples and freshly collected whole blood samples, respectively. LOD (experimentally obtained at 100 pg/mL (2.64 pM/0.9 IU/L)) was demonstrated to be up to ten times lower with more than six times faster sample preparation than what has previously been reported for on-paper analysis of hCG in human serum samples.


Assuntos
Gonadotropina Coriônica/sangue , Teste em Amostras de Sangue Seco/métodos , Papel , Sequência de Aminoácidos , Anticorpos Imobilizados/imunologia , Anticorpos Monoclonais/imunologia , Biomarcadores/sangue , Biomarcadores/química , Gonadotropina Coriônica/química , Gonadotropina Coriônica/imunologia , Cromatografia Líquida , Teste em Amostras de Sangue Seco/instrumentação , Humanos , Limite de Detecção , Espectrometria de Massas/instrumentação , Espectrometria de Massas/métodos , Proteólise , Reprodutibilidade dos Testes , Tripsina/química
10.
Anal Chim Acta ; 1084: 53-59, 2019 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-31519234

RESUMO

Single cell mass spectrometry (SCMS) allows for molecular analysis of individual cells while avoiding the inevitable drawbacks of using cell lysate prepared from populations of cells. Based on our previous design of the T-probe, a microscale sampling and ionization device for SCMS analysis, we further developed the device to perform online, and real time lysis of non-adherent live single cells for mass spectrometry (MS) analysis at ambient conditions. This redesigned T-probe includes three parts: a sampling probe with a small tip to withdraw a whole cell, a solvent-providing capillary to deliver lysis solution (i.e., acetonitrile), and a nano-ESI emitter in which rapid cell lysis and ionization occur followed by MS analysis. These three components are embedded between two polycarbonate slides and are jointed through a T-junction to form an integrated device. Colon cancer cells (HCT-116) under control and treatment (using anticancer drug irinotecan) conditions were analyzed. We detected a variety of intracellular species, and structural identification of selected ions was conducted using tandem MS (MS2). We further conducted statistical analysis (e.g., PLS-DA and t-test) to gain biological insights of cellular metabolism. Our results indicate that the influence of anticancer drugs on cellular metabolism of live non-adherent cells can be obtained using the SCMS experiments combined with statistical data analysis.


Assuntos
Nanotecnologia , Análise de Célula Única , Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Células HCT116 , Humanos , Metabolismo dos Lipídeos/efeitos dos fármacos , Espectrometria de Massas/instrumentação , Nanotecnologia/instrumentação , Análise de Célula Única/instrumentação , Células Tumorais Cultivadas
11.
J Mass Spectrom ; 54(9): 729-737, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31432563

RESUMO

Fentanyl and related psychoactive substances are at the forefront of the opioid overdose crisis, for which a complete solution is not immediately obvious. Drug testing for harm reduction may be an effective approach to both reduce overdoses and importantly, engage people who use drugs (PWUD) with the medical system. Paper spray mass spectrometry (PS-MS) is an ambient ionization strategy that is uniquely suited to address this complicated analytical task. This perspectives article presents the merits of PS-MS, with a focus upon the current state of its use as a candidate drug checking strategy for harm reduction. PS-MS is inherently sensitive and selective, with detection limits in the picogram range. It requires small drug samples (~1 mg) for quantitative drug testing, critical to encourage pre-consumption measurements by PWUD in the context of a harm reduction strategy. Calibrations obtained in surrogate drug matrices containing highly concentrated primary drugs demonstrate comparable sensitivities, a wide calibration range, and minimal matrix effects. PS-MS can be interfaced with high-resolution MS for non-targeted analysis, allowing the identification of novel psychoactive substances as they appear in street drugs. Individual quantitative PS-MS measurements for drug testing can be done in 1 minute or less, resulting in high sample throughput. Significant advancement in mass spectrometer miniaturization and mobilization has concomitant benefits for direct, on-site drug checking, such as reduced cost, simplified maintenance and ease of use by less skilled operators. While PS-MS technology continues to rapidly advance, it is our opinion that PS-MS can be utilized as an effective tool for harm reduction in the opioid overdose crisis.


Assuntos
Overdose de Drogas/prevenção & controle , Fentanila/análogos & derivados , Fentanila/análise , Drogas Ilícitas/análise , Espectrometria de Massas/instrumentação , Espectrometria de Massas/métodos , Psicotrópicos/análise , Redução do Dano , Ensaios de Triagem em Larga Escala/instrumentação , Ensaios de Triagem em Larga Escala/métodos , Humanos , Limite de Detecção , Miniaturização , Sensibilidade e Especificidade , Detecção do Abuso de Substâncias/métodos , Fatores de Tempo
12.
BMC Res Notes ; 12(1): 477, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31370856

RESUMO

OBJECTIVE: Short-chain triacylglycerols (TAGs) in lipid extracts of biological samples are not sufficiently resolved using conventional reversed-phase separation on two C18 columns in series, or using a two-dimensional chromatographic separation with a silver ion column as the second dimension (2D). An additional dimension of separation was required. RESULTS: The hardware and software components to allow a second second-dimension (2D) separation and three total separation dimensions were developed. Two contact closure (CC) activated 4-port, 2-position valves (4P2PVs) for ultra-high performance liquid chromatography (UHPLC) were joined together and used for one of two second dimensions in comprehensive two-dimensional liquid chromatography (2D-LC) coupled to four mass spectrometers simultaneously in parallel in an LC1MS2 × (LC1MS1 + LC1MS1) = LC3MS4 configuration. A timed contact closure circuit (TCCC) controlled the two UHPLC valves, operated by repetitive CCs for the 4P2PVs. The TCCC-controlled 4P2PVs were used to direct a portion of the 1D eluent to one of the two 2D's for separation by a quaternary UHPLC system that was not allowed by the commercial 2D-LC system. The 1D separation was a non-aqueous reversed-phase HPLC instrument used for separation of TAGs; the commercial 2D-LC 2D binary UHPLC was used for silver-ion chromatography of unsaturated TAGs; and the CC-controlled second 2D was used for separation of short-chain (SC) saturated TAGs.


Assuntos
Cromatografia Líquida de Alta Pressão/instrumentação , Cromatografia de Fase Reversa/instrumentação , Triglicerídeos/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia de Fase Reversa/métodos , Humanos , Espectrometria de Massas/instrumentação , Fatores de Tempo , Triglicerídeos/classificação
13.
Mol Omics ; 15(5): 348-360, 2019 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-31465043

RESUMO

Comprehensive proteome quantification is crucial for a better understanding of underlying mechanisms of diseases. Liquid chromatography mass spectrometry (LC-MS) has become the method of choice for comprehensive proteome quantification due to its power and versatility. Even though great advances have been made in recent years, full proteome coverage for complex samples remains challenging due to the high dynamic range of protein expression. Additionally, when studying disease regulatory proteins, biomarkers or potential drug targets are often low abundant, such as for instance kinases and transcription factors. Here, we show that with improvements in chromatography and data analysis the single shot proteome coverage can go beyond 10 000 proteins in human tissue. In a testis cancer study, we quantified 11 200 proteins using data independent acquisition (DIA). This depth was achieved with a false discovery rate of 1% which was experimentally validated using a two species test. We introduce the concept of hybrid libraries which combines the strength of direct searching of DIA data as well as the use of large project-specific or published DDA data sets. Remarkably deep proteome coverage is possible using hybrid libraries without the additional burden of creating a project-specific library. Within the testis cancer set, we found a large proportion of proteins in an altered expression (in total: 3351; 1453 increased in cancer). Many of these proteins could be linked to the hallmarks of cancer. For example, the complement system was downregulated which helps to evade the immune response and chromosomal replication was upregulated indicating a dysregulated cell cycle.


Assuntos
Cromatografia Líquida/instrumentação , Espectrometria de Massas/instrumentação , Células-Tronco Neoplásicas/química , Proteômica/métodos , Cromatografia Líquida/métodos , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Espectrometria de Massas/métodos , Células-Tronco Neoplásicas/metabolismo , Proteoma , Neoplasias Testiculares/metabolismo
14.
Anal Bioanal Chem ; 411(25): 6603-6614, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31317239

RESUMO

The topic of food analysis and safety has attracted increasing interest in recent decades owing to recent scandals concerning fraudulent activities (mislabeling, sophistication, adulteration, etc.) that can undermine human health. Among them, seafood fraud has probably the strongest relationship with food safety, an activity that goes beyond economic interests. This article explores the capabilities of an innovative instrumental setup, called the "iKnife," as a powerful tool in this specific research area, where until now genomics and proteomics have been the workhorses in analytical approaches. iKnife, which means "intelligent knife," is the name of a recent technology based on rapid evaporative ionization mass spectrometry (REIMS). REIMS is an emerging technique able to characterize different samples rapidly, affording a comprehensive profile usable as a fingerprint, without the need for preliminary extraction or cleanup procedures. In detail, a REIMS source is coupled to a high-resolution tandem mass spectrometer; such coupling allows one to maximize the amount of information (discriminant features) collected for a single analysis, as well as to focus on target analytes to achieve enhanced sensitivity and selectivity. A database was created from 18 marine species typical of the Mediterranean Sea, all caught in the very small area of the Strait of Messina, and reliable identification was achieved for each species with confidence higher than 99%. One big model and three submodels were built by principal component analysis and linear discriminant analysis for unambiguous key variable identification within each class (e.g., Cephalopoda), order (e.g., Perciformes), or family (e.g., Carangidae). Graphical abstract.


Assuntos
Peixes , Espectrometria de Massas/instrumentação , Alimentos Marinhos/análise , Animais , Análise Discriminante , Desenho de Equipamento , Peixes/classificação , Análise de Alimentos/instrumentação , Mar Mediterrâneo , Análise de Componente Principal , Alimentos Marinhos/classificação
15.
Medicina (Kaunas) ; 55(7)2019 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-31323919

RESUMO

Background and objectives: Anwar Ratol is one of the most famous cultivar of mango in South Asia, especially Pakistan. Mango leaves are left as food waste. This study evaluated the potential of mango (Anwar Ratol) leaves for their use against diabetes mellitus. Material and Methods: In this study, hydro-alcoholic extract of the plant leaves was prepared and evaluated by electrospray ionization mass spectroscopy (ESI-MS) and high-performance liquid chromatography (HPLC) for the presence of phytochemicals. The plant extract was administered to Alloxan induced diabetic mice followed by evaluation through oral glucose tolerance test; determination of postprandial glucose, body weight, lipid profile and histopathological evaluation of pancreas. Results: Chemical evaluation revealed the presence of mangiferin, rhamnetin, catechin, epicatechin, iriflophenone 3-C-ß-D-glucoside, gallic acid and other phenolic and flavonoid compounds. The plant extract exhibited a decrease in postprandial blood glucose following seven days therapy in diabetic mice. The extract also prevented the rise in blood glucose level as determined by glucose tolerance test in diabetic mice. Furthermore, therapy of diabetic mice with the extract prevented a decrease in body weight and decline in beta-cell mass associated with alloxan and improved lipid profile. Conclusion: The findings of the study clearly suggested that the leaf extract of the plant might possess anti-diabetic activity possibly due to the presence of mangiferin and other phytochemicals such as phenolic and flavonoid compounds. This study will serve as a basis for the use of mango leaf extract against diabetes. Furthermore, this study will also provide basis for the bioassay-based fractionation and isolation of active principles responsible for the antidiabetic potential of mango leaves.


Assuntos
Diabetes Mellitus/tratamento farmacológico , Hipoglicemiantes/normas , Extratos Vegetais/farmacologia , Análise de Variância , Animais , Glicemia/efeitos dos fármacos , Diabetes Mellitus/patologia , Diabetes Mellitus/fisiopatologia , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/etiologia , Hipoglicemiantes/uso terapêutico , Mangifera , Espectrometria de Massas/instrumentação , Espectrometria de Massas/métodos , Camundongos , Paquistão , Fitoterapia/métodos , Fitoterapia/normas , Extratos Vegetais/uso terapêutico
16.
Methods Mol Biol ; 2030: 69-83, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31347111

RESUMO

Single-compound analysis of stable or radioactive isotopes has found application in a number of fields ranging from archaeology to forensics. Often, the most difficult part of these analyses is the development of a method for isolating the compound(s) of interest, which can derive from a wide range of sample types including the hair, nails, and bone.Here we describe three complementary preparative HPLC techniques suitable for separating and isolating amino acids from bone collagen and hair keratin. Using preparative reversed-phase, ion-pair, or mixed-mode chromatography in aqueous carbon-free mobile phases, or those from which carbon can easily be removed, underivatized single amino acids can be isolated and further analyzed using mass spectrometric techniques.


Assuntos
Aminoácidos/isolamento & purificação , Cromatografia de Fase Reversa/métodos , Espectrometria de Massas/métodos , Datação Radiométrica/métodos , Aminoácidos/química , Animais , Osso e Ossos/química , Isótopos de Carbono/análise , Isótopos de Carbono/química , Radioisótopos de Carbono/análise , Radioisótopos de Carbono/química , Cromatografia Líquida de Alta Pressão/instrumentação , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia de Fase Reversa/instrumentação , Colágeno/química , Colágeno/isolamento & purificação , Cabelo/química , Humanos , Hidrólise , Espectrometria de Massas/instrumentação , Datação Radiométrica/instrumentação
17.
Methods Mol Biol ; 2030: 263-275, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31347124

RESUMO

The determination of the stereochemistry of common and unusual amino acids is important in food chemistry, archeology, medicine, and life sciences including such diverse areas as marine biology and extraterrestrial chemistry and has greatly contributed to our current knowledge in these fields.To determine the stereochemistry of amino acids, many chromatographic methods have been developed and refined over the last decades. Here we describe a state-of-the-art indirect chromatography-based LC-MS method. Diastereomers were formed from amino acids that were reacted with chiral derivatizing agents such as Marfey's reagent (FDAA), GITC, S-NIFE, and OPA-IBLC and separated on a reversed phase column using mass spectrometry compatible buffers.


Assuntos
Aminoácidos/análise , Espectrometria de Massas/métodos , Peptídeos/análise , Alanina/análogos & derivados , Alanina/química , Aminoácidos/química , Tampões (Química) , Cromatografia Líquida de Alta Pressão/instrumentação , Cromatografia Líquida de Alta Pressão/métodos , Dinitrobenzenos/química , Hidrólise , Isotiocianatos/química , Espectrometria de Massas/instrumentação , Nitrocompostos/química , Peptídeos/química , Estereoisomerismo
18.
Methods Mol Biol ; 2030: 429-438, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31347136

RESUMO

The amino acid profile obtained from a fingerprint may provide valuable information on its donor. Unfortunately, the collection of chemicals from the fingerprint is often destructive to the fingerprint ridge detail. Herein we detail the use of cross-linkable solutions of dextran-methacrylate to form hydrogels capable of collecting amino acids from surfaces followed by extraction and quantification with UPLC-MS. This method allows for the amino acid profile analysis of fingerprints while allowing for their increased visualization at a later stage using the standard method of cyanoacrylate fuming followed by basic-yellow dyeing.


Assuntos
Aminoácidos/isolamento & purificação , Reagentes para Ligações Cruzadas/química , Dermatoglifia , Espectrometria de Massas/métodos , Adsorção , Aminoácidos/química , Cromatografia Líquida de Alta Pressão/instrumentação , Cromatografia Líquida de Alta Pressão/métodos , Dextranos/química , Estudos de Viabilidade , Humanos , Hidrogéis/química , Espectrometria de Massas/instrumentação , Metacrilatos/química
19.
J Am Soc Mass Spectrom ; 30(9): 1720-1732, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31161333

RESUMO

Ambient mass spectrometry is a powerful approach for rapid, high-throughput, and direct sample analysis. Due to the open-air desorption and ionization processes, random fluctuations of ambient conditions can lead to large variances in mass-spectral signals over time. The mass-spectral data also can be further complicated due to multiple analytes present in the sample, background-ion signals stemming from the desorption/ionization source itself, and other laboratory-specific conditions (e.g., ambient laboratory air, nearby hardware). Thus, background removal and analyte-ion recognition can be quite difficult, particularly in non-targeted analyses. Here, we demonstrate the use of a cross-correlation-based approach to exploit chemical information encoded in the time domain to group/categorize mass-spectral peaks from a single analysis dataset. Ions that originate from ambient (or other) background species were readily flagged and removed from spectra; the result was a decrease in mass-spectral complexity by over 70% due to the removal of these background ions. Meanwhile, analyte ions were differentiated and categorized based on their time-domain profiles. With sufficient mass resolving-power and mass-spectral acquisition rate, isolated mass spectra containing ions from the same species in a sample could be extracted, leading to a reduction in mass-spectral complexity by more than 98% in some cases. The cross-correlation approach was tested with different ionization sources as well as reproducible and irreproducible sample introduction. Software built in-house enabled fully automated data processing, which can be performed within a few seconds. Ultimately, this approach provides an additional dimension of analyte separation in ambient mass-spectrometric analyses with information that is already recorded throughout the analysis.


Assuntos
Espectrometria de Massas/métodos , Processamento de Sinais Assistido por Computador , Pressão Atmosférica , Automação Laboratorial , Íons/análise , Espectrometria de Massas/instrumentação , Praguicidas/análise , Praguicidas/química , Software , Ácido gama-Aminobutírico/análise
20.
J Am Soc Mass Spectrom ; 30(9): 1713-1719, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31209791

RESUMO

Global consumption of complementary and alternative medicines, including herbal medicines, has increased substantially, and recent reports of adulteration demonstrate the need for high throughput and extensive pharmacovigilance to ensure product safety and quality. Three different standard reference materials and five previously analyzed herbal medicines have been used as a proof of concept for the application of adulteration/contamination screening using a Direct Sample Analysis (DSA) ion source with TOF MS on the Perkin Elmer AxION 2 TOF. This technique offers the advantages of minimum sample preparation, rapid analysis, and mass accuracies of 5 ppm. The DSA TOF analysis correlates well with the previous analysis on the initial sample set (which found undeclared herbal ingredients), with the added advantage of detecting previously untargeted compounds, including species-specific flavonoids and alkaloids. The rapid analysis using the DSA-TOF facilitates screening for hundreds of compounds in minutes with minimal sample preparation, generating a comprehensive profile for each sample. Graphical Abstract.


Assuntos
Contaminação de Medicamentos , Espectrometria de Massas/métodos , Preparações de Plantas/análise , Camellia sinensis/química , Cápsulas/análise , Terapias Complementares , Ginkgo biloba/química , Espectrometria de Massas/instrumentação , Espectrometria de Massas/normas , Padrões de Referência , Comprimidos/análise , Chá/química , Vitaminas/análise
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