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Development and validation of a multi-residue and multiclass ultra-high-pressure liquid chromatography-tandem mass spectrometry screening of antibiotics in milk

Freitas, Andreia; Barbosa, Jorge; Ramos, Fernando
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
105.88%
A multi-residue screening method for 33 antibiotics from five different families was employed to simultaneously determine sulphonamide, tetracycline, macrolide, quinolone and chloramphenicol antibiotics using ultra high pressure liquid chromatography tandem mass spectrometry. A simple sample preparation method was developed using protein precipitation, centrifugation and solid phase extraction and was optimised to achieve the best recovery for all compounds. The methodology was validated for quantitative screening methods, by evaluating the detection capability (CCβ), specificity, selectivity, precision, applicability and ruggedness. Precision, in terms of relative standard deviation, was under 21% for all compounds. Because CCβ was determined for screening purposes and, according to maximum residue limit, the limit of detection of the method was calculated and ranged from 0.010 μg kg−1 to 3.7 μg kg−1. This validation provided evidence that the method is suitable to be applied in routine analysis for the detection of antibiotics in bovine, caprine and ovine milk.

Multidetection of antibiotics in liver tissue by Ultra-High-Pressure-Liquid-Chromatography tandem Mass Spectrometry

Freitas, Andreia; Barbosa, Jorge; Ramos, Fernando
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
105.88%
A multiresidue quantitative screening method covering 39 antibiotics from 7 different families by Ultra-High-Pressure-Liquid-Chromatography tandem Mass Spectrometry (UHPLC-MS/MS) is described. Sulfonamides, trimethoprim, tetracyclines, macrolides, quinolones, penicillins and chloramphenicol are simultaneously detected in liver tissue. A simple sample treatment method consisting of extraction with a mixture of acetonitrile and ethylenediaminetetraacetic acid (EDTA) followed by solid-phase extraction (SPE) with a hydrophilic-lipophilic balanced (HLB) cartridge was developed. The methodology was validated, in accordance with Decision 2002/657/EC, by evaluating the following required parameters: decision limit (CCα), detection capability (CCβ), specificity, repeatability and reproducibility. The precision, in terms of the relative standard deviation, was under 22% for all of the compounds, and the recoveries were between 80% and 110%. The CCα and CCβ were determined according to the maximum residue limit (MRL) or the minimum required performance limit (MRPL), when established.

Estudo de alcaloides dos frutos de Passiflora alata e de Passiflora edulis por SBSE, CLAE-Flu e identificação por CLUE-EM; Alkaloids studies from Passiflora alata and Passiflora edulis fruits analyzed by SBSE, CLAE-Flu, and identified by CLUE-EM.

Silva, Gabriela Ribeiro
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 15/05/2015 PT
Relevância na Pesquisa
55.84%
O maracujá, nome popular atribuído ao fruto das diversas espécies do gênero Passiflora, da família Passifloraceae, é amplamente comercializado e consumido no mundo, sendo o Brasil um dos maiores produtores do fruto. Alguns estudos apontam possível toxicidade relacionada às espécies de Passiflora, principalmente P. incarnata. No entanto, há pouco conhecimento acerca das espécies P. edulis e P. alata, sobretudo em relação à polpa e sementes. Os extratos da polpa e das sementes dos frutos dessas duas espécies de "maracujá", Passiflora alata e Passiflora edulis, foram estudados com o objetivo de identificar alcaloides harmânicos, pelo preparo das amostras por extração por sorção em barra magnética recoberta com polidimetilsiloxano (SBSE-PDMS) e SBSE recoberta com polietilenoglicol silicone (SBSE-EG Silicone) e análise por cromatografia líquida de alta eficiência com detector por fluorescência (CLAE-Flu) e cromatografia líquida de ultra eficiência acoplada à espectrometria de massas sequencial (CLUE-EM/EM). A análise dos alcaloides harmana e harmina nos extratos da polpa de P. alata foi feita por meio do método de adição de padrão e mostrou menor quantidade destes alcaloides, em comparação com os resultados da análise dos extratos da polpa dos frutos de P. edulis...

High resolution ultra high pressure liquid chromatography-time-of-flight mass spectrometry dereplication strategy for the metabolite profiling of Brazilian Lippia species

Funari, Cristiano S.; Eugster, Philippe J.; Martel, Sophie; Carrupt, Pierre-Alain; Wolfender, Jean-Luc; Silva, Dulce Helena S.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 167-178
ENG
Relevância na Pesquisa
65.67%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Plants belonging to the Lippia genus have been widely used in ethnobotany throughout South and Central America and in tropical Africa as foods, medicines, sweeteners and in beverage flavouring. Various taxonomic problems involving some genera from Verbenaceae, including Lippia. have been reported. In this study, the metabolite profiling of fifteen extracts of various organs of six Lippia species was performed and compared using UHPLC-PDA-TOF-MS. Fourteen phenolic compounds that were previously isolated from L salviaefolia Cham. and L lupulina Cham. were used as references. The annotation of the remaining LC peaks was based on concomitant online high mass accuracy measurements and subsequent molecular formula assignments following these different steps: (i) elimination of non-coherent putative molecular formulae by heuristic filtering, (ii) verification of the occurrence of remaining molecular formulae in databases. (iii) cross search with reported compounds in the Lippia genus, (iv) match with reported UV spectra, (v) estimation of the chromatographic retention behaviour based on the log P parameter of reference compounds. This strategy is generic and time-saving...

Rapid Catalyst Screening by a Continuous-Flow Microreactor Interfaced with Ultra High Pressure Liquid Chromatography

Fang, Hui; Xiao, Qing; Wu, Fanghui; Floreancig, Paul E.; Weber, Stephen G.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 20/08/2010 EN
Relevância na Pesquisa
105.91%
A high-throughput screening system for homogeneous catalyst discovery has been developed by integrating a continuous-flow capillary-based microreactor with ultra-high pressure liquid chromatography (UHPLC) for fast online analysis. Reactions are conducted in distinct and stable zones in a flow stream that allows for time and temperature regulation. UHPLC detection at high temperature allows high throughput online determination of substrate, product, and byproduct concentrations. We evaluated the efficacies of a series of soluble acid catalysts for an intramolecular Friedel-Crafts addition into an acyliminium ion intermediate within one day and with minimal material investment. The effects of catalyst loading, reaction time, and reaction temperature were also screened. This system exhibited high reproducibility for high-throughput catalyst screening and allowed several acid catalysts for the reaction to be identified. Major side products from the reactions were determined through off-line mass spectrometric detection. Er(OTf)3, the catalyst that showed optimal efficiency in the screening, was shown to be effective at promoting the cyclization reaction on a preparative scale.

Triacylglycerol profiling of microalgae strains for biofuel feedstock by liquid chromatography–high-resolution mass spectrometry

MacDougall, Karen M.; McNichol, Jesse; McGinn, Patrick J.; O’Leary, Stephen J. B.; Melanson, Jeremy E.
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
75.81%
Biofuels from photosynthetic microalgae are quickly gaining interest as a viable carbon-neutral energy source. Typically, characterization of algal feedstock involves breaking down triacylglycerols (TAG) and other intact lipids, followed by derivatization of the fatty acids to fatty acid methyl esters prior to analysis by gas chromatography (GC). However, knowledge of the intact lipid profile could offer significant advantages for discovery stage biofuel research such as the selection of an algal strain or the optimization of growth and extraction conditions. Herein, lipid extracts from microalgae were directly analyzed by ultra-high pressure liquid chromatography–mass spectrometry (UHPLC-MS) using a benchtop Orbitrap mass spectrometer. Phospholipids, glycolipids, and TAGs were analyzed in the same chromatographic run, using a combination of accurate mass and diagnostic fragment ions for identification. Using this approach, greater than 100 unique TAGs were identified over the six algal strains studied and TAG profiles were obtained to assess their potential for biofuel applications. Under the growth conditions employed, Botryococcus braunii and Scenedesmus obliquus yielded the most comprehensive TAG profile with a high abundance of TAGs containing oleic acid.

System-wide Perturbation Analysis with Nearly Complete Coverage of the Yeast Proteome by Single-shot Ultra HPLC Runs on a Bench Top Orbitrap*

Nagaraj, Nagarjuna; Alexander Kulak, Nils; Cox, Juergen; Neuhauser, Nadin; Mayr, Korbinian; Hoerning, Ole; Vorm, Ole; Mann, Matthias
Fonte: The American Society for Biochemistry and Molecular Biology Publicador: The American Society for Biochemistry and Molecular Biology
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
65.73%
Yeast remains an important model for systems biology and for evaluating proteomics strategies. In-depth shotgun proteomics studies have reached nearly comprehensive coverage, and rapid, targeted approaches have been developed for this organism. Recently, we demonstrated that single LC-MS/MS analysis using long columns and gradients coupled to a linear ion trap Orbitrap instrument had an unexpectedly large dynamic range of protein identification (Thakur, S. S., Geiger, T., Chatterjee, B., Bandilla, P., Frohlich, F., Cox, J., and Mann, M. (2011) Deep and highly sensitive proteome coverage by LC-MS/MS without prefractionation. Mol. Cell Proteomics 10, 10.1074/mcp.M110.003699). Here we couple an ultra high pressure liquid chromatography system to a novel bench top Orbitrap mass spectrometer (Q Exactive) with the goal of nearly complete, rapid, and robust analysis of the yeast proteome. Single runs of filter-aided sample preparation (FASP)-prepared and LysC-digested yeast cell lysates identified an average of 3923 proteins. Combined analysis of six single runs improved these values to more than 4000 identified proteins/run, close to the total number of proteins expressed under standard conditions, with median sequence coverage of 23%. Because of the absence of fractionation steps...

Neutral Fragment Filtering for Rapid Identification of New Diester-Diterpenoid Alkaloids in Roots of Aconitum carmichaeli by Ultra-High-Pressure Liquid Chromatography Coupled with Linear Ion Trap-Orbitrap Mass Spectrometry

Zhang, Jing; Huang, Zhi Hai; Qiu, Xiao Hui; Yang, Yi Ming; Zhu, Da Yuan; Xu, Wen
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 21/12/2012 EN
Relevância na Pesquisa
105.89%
A rapid and effective method was developed for separation and identification of diester-diterpenoid alkaloids (DDA) in the roots of Aconitum carmichaeli by ultra-high-pressure liquid chromatography coupled with high resolution LTQ-Orbitrap tandem mass spectrometry (UHPLC-LTQ-Orbitrap-MSn). According to accurate mass measurement and the characteristic neutral loss filtering strategy, a total of 42 diester-diterpenoid alkaloids (DDA) were rapidly detected and characterized or tentatively identified. Meanwhile, the proposed fragmentation pathways and the major diagnostic fragment ions of aconitine, mesaconitine and hypaconitine were investigated to trace DDA derivatives in crude plant extracts. 23 potential new compounds were successfully screened and characterized in Aconitum carmichaeli, including 16 short chain fatty acyls DDA, 4 N-dealkyl DDA and several isomers of aconitine, mesaconitine and hypaconitine.

A concept study on non-targeted screening for chemical contaminants in food using liquid chromatography–mass spectrometry in combination with a metabolomics approach

Tengstrand, Erik; Rosén, Johan; Hellenäs, Karl-Erik; Åberg, K. Magnus
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
75.81%
A generic method to screen for new or unexpected contaminants at ppm levels in food has been developed. The method comprises an acidic acetonitrile extraction, detection with ultra-high-pressure liquid chromatography coupled to electrospray ionisation time-of-flight mass spectrometry and statistical evaluation using a metabolomics approach comparing suspected contaminated food with uncontaminated foods. The method was tested for 26 model contaminants from 100 μg/g down to 0.4 μg/g in three brands of fresh orange juice. Blinded statistical evaluation revealed signals from all added contaminants detectable by liquid chromatography–electrospray ionisation using positive ionisation mode, while only two false-positive signals were reported. The method is primarily intended to be used for investigation of food samples suspected to be contaminated with unknown substances. Additionally it could be used to continuously monitor for appearance of new food contaminants as a complement to the specific targeted analysis that is today’s foundation of food safety analysis.

Method Development and Validation for Ultra-High Pressure Liquid Chromatography/Tandem Mass Spectrometry Determination of Multiple Prostanoids in Biological Samples

Yu, Rui; Zhao, Guiqing; Christman, John W.; Xiao, Lei; van Breemen, Richard B.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em //2013 EN
Relevância na Pesquisa
85.78%
Following oxygenation of arachidonic acid by cyclooxygenase to form prostaglandin H2 (PGH2), a variety of prostanoids can be generated with diverse physiologic effects on pain, inflammation, allergy, cardiovascular system, cancer, etc. To facilitate the quantitative analysis of prostanoids in human serum of cell culture, an ultra-high pressure LC (UHPLC)/MS/MS method was developed and validated for the measurement of six eicosanoids belonging to the cyclooxygenase pathway: PGE2, PGD2, 8-iso-PGF2α, PGF2α, 6-keto-PGF1α, and thromboxane B2 (TXB2). Selectivity, matrix effects, calibration model, precision, and accuracy (intraday and interday), lower limit of quantitation (LLOQ), recovery, stability, and sample dilution were evaluated. Fast UHPLC separation was carried out in only 0.5 min with isocratic elution, and each prostanoid was measured using negative electrospray ionization MS with collision-induced dissociation and selected reaction monitoring. UHPLC/MS/MS provided high throughput with peak widths of approximately 3 s and an LLOQ of 0.020 ng/mL for PGE2, 0.027 ng/mL for PGD2, 0.152 ng/mL for 8-iso-PGF2α, 0.179 ng/mL for PGF2α and 6-keto-PGF1α, and 0.013 ng/mL for TXB2.

Ultra-High Pressure Fast Size Exclusion Chromatography for Top-Down Proteomics

Chen, Xin; Ge, Ying
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
65.94%
Top-down mass spectrometry (MS)-based proteomics has gained a solid growth over the past few years but still faces significant challenges in the liquid chromatographic separation of intact proteins. In top-down proteomics, it is essential to separate the high mass proteins from the low mass species due to the exponential decay in S/N as a function of increasing molecular mass. Size exclusion chromatography (SEC) is a favored liquid chromatography method for size-based separation of proteins but suffers from notoriously low resolution and detrimental dilution. Herein we reported the use of ultra-high pressure (UHP) SEC for rapid and high-resolution separation of intact proteins for top-down proteomics. Fast separation of intact proteins (6 – 669 kDa) was achieved in less than 7 min with high-resolution and high efficiency. More importantly, we have shown that this UHP-SEC provides high-resolution separation of intact proteins using a MS-friendly volatile solvent system, allowing the direct top-down MS analysis of SEC eluted proteins without an additional desalting step. Taken together, we have demonstrated that UHP-SEC is an attractive LC strategy for the size-separation of proteins with great potential for top-down proteomics.

Fast analysis of 29 polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs with ultra-high performance liquid chromatography-atmospheric pressure photoionization-tandem mass spectrometry

Lung, Shih-Chun Candice; Liu, Chun-Hu
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 12/08/2015 EN
Relevância na Pesquisa
85.88%
Polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs are ubiquitous in the environment. Some of them are probable carcinogens and some are source markers. This work presents an ultra-high performance liquid chromatography-atmospheric pressure photoionization-tandem mass spectrometry (UHPLC-APPI-MS/MS) method for simultaneous analysis of 20 PAHs and nine nitro-PAHs. These compounds are separated in 15 minutes in the positive mode and 11 minutes in the negative mode, one half of GC/MS analysis time. Two pairs of precursor/product ions are offered, which is essential for confirmation. This method separates and quantifies benzo[a]pyrene (the most toxic PAHs) and non-priority benzo[e]pyrene (isomers, little toxicity) to avoid overestimation of toxin levels, demonstrating its importance for health-related researches. With 0.5% 2,4-difluoroanisole in chlorobenzene as the dopant, limits of detection of PAHs except acenaphthylene and those of nitro-PAHs except 2-nitrofluoranthene are below 10 pg and 3 pg, respectively, mostly lower than or comparable to those reported using LC-related systems. The responses were linear over two orders of magnitude with fairly good accuracy and precision. Certified reference materials and real aerosol samples were analyzed to demonstrate its applicability. This fast...

Seradyn quantitative microsphere system lamotrigine immunoassay on a Hitachi 911 analyzer compared with HPLC-UV

Westley, I.; Morris, R.
Fonte: Lippincott Williams & Wilkins Publicador: Lippincott Williams & Wilkins
Tipo: Artigo de Revista Científica
Publicado em //2008 EN
Relevância na Pesquisa
65.77%
Lamotrigine (LTG) is used currently as monotherapy or, more frequently, as add-on therapy with other antiepileptic drugs. It demonstrates efficacy against partial seizures, primary and secondary tonic clonic seizures, absence seizures, and drop attacks. LTG pharmacokinetics is complicated by coadministration with other antiepileptic drugs such as valproic acid, phenytoin, or carbamazepine. The wide interpatient variability in LTG dosage required to attain therapeutic plasma LTG concentrations for seizure control suggests that LTG is a good candidate for therapeutic drug monitoring (TDM). In this study, we compared the quantitative microsphere system (QMS) LTG immunoassay with the LTG high-performance liquid chromatography-ultra violet (HPLC-UV) assay routinely employed for TDM in our laboratory. Samples tested by these methods were patient samples presented for TDM and from a quality assurance program. Quality control material demonstrated within- and between-run (n = 6) coefficient of variation and biases of less than 10%. Patient samples demonstrated a Deming regression of QMS = 1.09 HPLC-UV - 0.17 and quality assurance program samples had a Deming regression of QMS = 1.03 HPLC-UV - 0.11. Patient samples demonstrated a mean bias of 6.1% and quality assurance program samples had a mean bias of 0.2%. The QMS LTG assay had a clinically small but significant overestimation of plasma LTG concentrations. It may be useful as a convenient alternative method that would provide TDM guidance if a chromatographic assay was not available.; Westley...

Investigation of monomeric and oligomeric wine stilbenoids in red wines by ultra-high-performance liquid chromatography/electrospray ionization quadrupole time-of-flight mass spectrometry

Moss, R.; Mao, Q.; Taylor, D.; Saucier, C.
Fonte: John Wiley & Sons Ltd Publicador: John Wiley & Sons Ltd
Tipo: Artigo de Revista Científica
Publicado em //2013 EN
Relevância na Pesquisa
105.88%
RATIONALE: Stilbenoids are secondary plant metabolites responsible for the protection of multiple plant species including grape vine from bacterial and fungal infection. Red wine has been shown to be a major source of these compounds in the human diet, where they display an array of health benefits. Providing a more complete profile of the stilbenoids present in red wine, this study detects 41 stilbenoid compounds, 23 of which have never before been detected in red wine. METHODS: Red wine extracts were scanned using an ultra-high-performance liquid chromatograph coupled to a hybrid quadrupole time-of-flight mass analyzer. Multiple targeted MS/MS precursor ion scan experiments were performed using electrospray ionization operated in negative mode. Precursor ion masses were scanned for the monomeric and oligomeric stilbenoids, as well as modifications such as O-glycosylation, methoxylation and oxidation products of these compounds. Accurate mass precursor and characteristic product ions afforded partial structural elucidation and assignment of these compounds. RESULTS: A total of 41 (both known and novel) stilbenoids were detected in extracted red wine. In addition to the well-known monomeric stilbenes, several resveratrol-resveratrol homodimers (m/z 453.1344)...

Analysis of polar organic contaminants in surface water of the northern Adriatic Sea by solid-phase extraction followed by ultrahigh-pressure liquid chromatography–QTRAP® MS using a hybrid triple-quadrupole linear ion trap instrument

LOOS Robert; TAVAZZI SIMONA; PARACCHINI Bruno; CANUTI Elisabetta; WEISSTEINER Christof
Fonte: SPRINGER HEIDELBERG Publicador: SPRINGER HEIDELBERG
Tipo: Articles in Journals Formato: Printed
ENG
Relevância na Pesquisa
85.8%
Water soluble polar organic contaminants are discharged by rivers, cities, or ships into the oceans. Little is known on the fate, pollution effects, and thresholds of toxic chemical mixtures in the marine environment. A new trace analytical method was developed for the multi-compound analysis of polar organic chemical contaminants in marine waters. The method is based on automated solid-phase extraction (SPE) of one liter water samples followed by ultra-high pressure liquid chromatography triple-quadrupole linear ion-trap mass spectrometry (UHPLC–QTRAP®-MS). Marine water samples from the open Adriatic Sea taken 16 km off-shore Venice (Italy) were analyzed. Method limits of quantification (LOQs) in the low picogram per liter (pg/l) concentration range were achieved. Out of the 67 target chemicals analyzed, 45 substances could be detected above the LOQ. The chemicals detected at the highest concentrations were caffeine (up to 367 ng/l), nitrophenol (36 ng/l), 2,4-dinitrophenol (34 ng/l), 5-methyl-1H-benzotriazole (18.5 ng/l), sucralose (11 ng/l), 1H-benzotriazole (9.2 ng/l), terbutylazine (9 ng/l), alachlor (7.7 ng/l), atrazine-desisopropyl (6.6 ng/l), diethyltoluamid (DEET) (5.0 ng/l), terbutylazine-desethyl (4.3 ng/l), metolachlor (2.8 ng/l)...

Rapid and sensitive ultra-high-pressure liquid chromatography method for quantification of antichagasic benznidazole in plasma: application in a preclinical pharmacokinetic study

Davanço, Marcelo Gomes; Campos, Michel Leandro de; Peccinini, Rosângela Gonçalves
Fonte: Wiley-Blackwell Publicador: Wiley-Blackwell
Tipo: Artigo de Revista Científica Formato: 1008-1015
ENG
Relevância na Pesquisa
105.88%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 09/51075-5; Processo FAPESP: 11/11239-9; Benznidazole (BNZ) and nifurtimox are the only drugs available for treating Chagas disease. In this work, we validated a bioanalytical method for the quantification of BNZ in plasma aimed at improving sensitivity and time of analysis compared with the assays already published. Furthermore, we demonstrated the application of the method in a preclinical pharmacokinetic study after administration of a single oral dose of BNZ in Wistar rats. A Waters (R) Acquity UHPLC system equipped with a UV-vis detector was employed. The method was established using an Acquity (R) UHPLC HSS SB C-18 protected by an Acquity (R) UHPLC HSS SB C-18 VanGuard guard column and detection at 324 nm(.) The mobile phase consisted of ultrapure water-acetonitrile (65:35), and elution was isocratic. The mobile phase flow rate was 0.55 mL/min, the volume of injection was 1 L, and the run time was just 2 min. The samples were kept at 25 degrees C until injection and the column at 45 degrees C for the chromatographic separation. The sample preparation was performed by a rapid protein precipitation with acetonitrile. The linear concentration range was 0.15-20 mu g/mL. The pharmacokinetic parameters of BNZ in rats were determined and the method was considered sensitive...

A sensitive microextraction by packed sorbent-based methodology combined with ultra-high pressure liquid chromatography as a powerful technique for analysis of biologically active flavonols in wines

Silva, Catarina L.; Gonçalves, João L.; Câmara, José S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /08/2012 ENG
Relevância na Pesquisa
156.02%
A new approach based on microextraction by packed sorbent (MEPS) and reversed-phase high-throughput ultra high pressure liquid chromatography (UHPLC) method that uses a gradient elution and diode array detection to quantitate three biologically active flavonols in wines, myricetin, quercetin, and kaempferol, is described. In addition to performing routine experiments to establish the validity of the assay to internationally accepted criteria (selectivity, linearity, sensitivity, precision, accuracy), experiments are included to assess the effect of the important experimental parameters such as the type of sorbent material (C2, C8, C18, SIL, and C8/SCX), number of extraction cycles (extract-discard), elution volume, sample volume, and ethanol content, on the MEPS performance. The optimal conditions of MEPS extraction were obtained using C8 sorbent and small sample volumes (250 μL) in five extraction cycle and in a short time period (about 5 min for the entire sample preparation step). Under optimized conditions, excellent linearity View the MathML source(Rvalues2>0.9963), limits of detection of 0.006 μg mL−1 (quercetin) to 0.013 μg mL−1 (myricetin) and precision within 0.5–3.1% were observed for the target flavonols. The average recoveries of myricetin...

Development of a novel microextraction by packed sorbent-based approach followed by ultrahigh pressure liquid chromatography as a powerful technique for quantification phenolic constituents of biological interest in wines

Gonçalves, João; Mendes, Berta; Silva, Catarina L.; Câmara, José S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /03/2012 ENG
Relevância na Pesquisa
95.88%
A novel analytical approach, based on a miniaturized extraction technique, the microextraction by packed sorbent (MEPS), followed by ultrahigh pressure liquid chromatography (UHPLC) separation combined with a photodiode array (PDA) detection, has been developed and validated for the quantitative determination of sixteen biologically active phenolic constituents of wine. In addition to performing routine experiments to establish the validity of the assay to internationally accepted criteria (linearity, sensitivity, selectivity, precision, accuracy), experiments are included to assess the effect of the important experimental parameters on the MEPS performance such as the type of sorbent material (C2, C8, C18, SIL, and M1), number of extraction cycles (extract-discard), elution volume, sample volume, and ethanol content, were studied. The optimal conditions of MEPS extraction were obtained using C8 sorbent and small sample volumes (250 μL) in five extraction cycle and in a short time period (about 5 min for the entire sample preparation step). The wine bioactive phenolics were eluted by 250 μL of the mixture containing 95% methanol and 5% water, and the separation was carried out on a HSS T3 analytical column (100 mm × 2.1 mm, 1.8 μm particle size) using a binary mobile phase composed of aqueous 0.1% formic acid (eluent A) and methanol (eluent B) in the gradient elution mode (10 min of total analysis). The method gave satisfactory results in terms of linearity with r2-values > 0.9986 within the established concentration range. The LOD varied from 85 ng mL−1 (ferulic acid) to 0.32 μg mL−1 ((+)-catechin)...

A new and improved strategy combining a dispersive-solid phase extraction-based multiclass method with ultra high pressure liquid chromatography for analysis of low molecular weight polyphenols in vegetables

Silva, Catarina L.; Haesen, Nathaly; Câmara, José S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /10/2012 ENG
Relevância na Pesquisa
85.82%
This paper reports on the development and optimization of a modified Quick, Easy, Cheap Effective, Rugged and Safe (QuEChERS) based extraction technique coupled with a clean-up dispersive-solid phase extraction (dSPE) as a new, reliable and powerful strategy to enhance the extraction efficiency of free low molecular-weight polyphenols in selected species of dietary vegetables. The process involves two simple steps. First, the homogenized samples are extracted and partitioned using an organic solvent and salt solution. Then, the supernatant is further extracted and cleaned using a dSPE technique. Final clear extracts of vegetables were concentrated under vacuum to near dryness and taken up into initial mobile phase (0.1% formic acid and 20% methanol). The separation and quantification of free low molecular weight polyphenols from the vegetable extracts was achieved by ultrahigh pressure liquid chromatography (UHPLC) equipped with a phodiode array (PDA) detection system and a Trifunctional High Strength Silica capillary analytical column (HSS T3), specially designed for polar compounds. The performance of the method was assessed by studying the selectivity, linear dynamic range, the limit of detection (LOD) and limit of quantification (LOQ)...

A fast method using a new hydrophilic–lipophilic balanced sorbent in combination with ultra-high performance liquid chromatography for quantification of significant bioactive metabolites in wines

Silva, Catarina L.; Pereira, Jorge; Wouter, Van G.; Giró, Carme; Câmara, José S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /10/2011 ENG
Relevância na Pesquisa
125.99%
This manuscript describes the development and validation of an ultra-fast, efficient, and high throughput analytical method based on ultra-high performance liquid chromatography (UHPLC) equipped with a photodiode array (PDA) detection system, for the simultaneous analysis of fifteen bioactive metabolites: gallic acid, protocatechuic acid, (−)-catechin, gentisic acid, (−)-epicatechin, syringic acid, p-coumaric acid, ferulic acid, m-coumaric acid, rutin, trans-resveratrol, myricetin, quercetin, cinnamic acid and kaempferol, in wines. A 50-mm column packed with 1.7-μm particles operating at elevated pressure (UHPLC strategy) was selected to attain ultra-fast analysis and highly efficient separations. In order to reduce the complexity of wine extract and improve the recovery efficiency, a reverse-phase solid-phase extraction (SPE) procedure using as sorbent a new macroporous copolymer made from a balanced ratio of two monomers, the lipophilic divinylbenzene and the hydrophilic N-vinylpyrrolidone (Oasis™ HLB), was performed prior to UHPLC–PDA analysis. The calibration curves of bioactive metabolites showed good linearity within the established range. Limits of detection (LOD) and quantification (LOQ) ranged from 0.006 μg mL−1 to 0.58 μg mL−1...