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HPLC-DAD-MS/MS-ESI screening of phenolic compounds in Pieris brassicae L. reared on Brassica rapa var. rapa L..

Ferreres, F.; Valentão, P.; Pereira, J.A.; Bento, Albino; Noites, A.; Seabra, R.M.; Andrade, P.B.
Fonte: ACS Publicador: ACS
Tipo: Artigo de Revista Científica
ENG
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The phenolic profiles of cabbage white butterfly (Pieris brassicae L.; Lepidoptera: Pieridae) at different development stages (larvae, exuviae, and butterfly), its excrements, and its host plant Brassica rapa var. rapa L. were determined by high performance liquid chromatography- diode-array detector-mass spectrometry/mass spectrometry-electrospray ionization (HPLC-DAD-MS/MS-ESI). Twenty-five acylated and nonacylated flavonoid glycosides and ferulic and sinapic acids were identified in host plant, from which only 12 compounds were found in the excrements. In addition, the excrements showed the presence of sulfate flavonoids and other flavonoid glycosides that were not detected in the leaves. In the larvae kept without food for 12 h, only 3 compounds common to the plant material and 2 others, also present in the excrements, were characterized. The results indicate that deacylation, deglycosylation, and sulfating steps are involved in the metabolic process of P. brassicae and that its excrements may constitute a promising source of bioactive compounds, which could be used to take profit of this common pest of Brassica cultures.

Phenolic acids determination by HPLC-DAD-ESI/MS in sixteen different portuguese wild mushrooms species

Barros, Lillian; Dueñas, Montserrat; Ferreira, Isabel C.F.R.; Baptista, Paula; Santos-Buelga, Celestino
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
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Analysis of phenolic compounds in sixteen Portuguese wild mushrooms species has been carried out by high-performance liquid chromatography coupled to photodiode array detector and mass spectrometer (HPLC–DAD–ESI/MS). No flavonoids were detected in the analysed samples, but diverse phenolic acids namely protocatechuic, p-hydroxybenzoic and p-coumaric acids, and two vanillic acid isomers were found and quantified. A related non-phenolic compound, cinnamic acid, was also detected in some samples, being the only compound found in Cantharellus cibarius (14.97 mg/kg, dry matter), Lycoperdon perlatum (14.36 mg/kg) and Macrolepiota procera (21.53 mg/kg). p-Hydroxybenzoic acid was found in the majority of the samples, being the most abundant compound in Agaricus silvicola (238.7 mg/kg). Ramaria botrytis showed the highest phenolic acids concentration (356.7 mg/kg) due to the significant contribution of protocatechuic acid (342.7 mg/kg).

Characterization of phenolic compounds in wild medicinal flowers from Portugal by HPLC-DAD-ESI/MS and evaluation of antifungal properties

Barros, Lillian; Alves, Carlos Tiago; Dueñas, Montserrat; Silva, Sónia; Oliveira, Rosário; Carvalho, Ana Maria; Henriques, Mariana; Santos-Buelga, Celestino; Ferreira, Isabel C.F.R.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
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In the present work, the phenolic compounds of Castanea sativa, Filipendula ulmaria and Rosa micrantha flowers from Northeastern Portugal were characterized by HPLC-DAD-ESI/MS. Furthermore, it was performed a screening of their antifungal potential against Candida species (C. albicans, C. glabrata, C. parapsilosis and C. tropicalis). C. sativa sample gave the highest amount of phenolic compounds (18973 ± 40 µg/g, fw) and hydrolysable tannins (14873 ± 110 µg/g). The highest amounts of phenolic acids (569 ± 20 µg/g) and flavonoids (6090 ± 253 µg/g) were obtained in F. ulmaria and R. micrantha samples, respectively. Hydrolysable tannins (e.g. tri and digalloyl HHDP glucose) were the main group of phenolic compounds in C. sativa and F. ulmaria samples, while flavonoids (e.g. (+)-catechin and procyanidin dimers and trimers) were the most abundant group in R. micrantha. Thus, the stronger effect showed by this latter against all the Candida species (MIC ≤ 0.155 mg/mL) and, particularly its fungicide effects in C. glabrata, might be related to the mentioned flavonoids that were inexistence in the other samples.

Forensic intoxication with clobazam: HPLC/DAD/MSD analysis

Proença, Paula; Teixeira, Helena; Pinheiro, João; Marques, Estela P.; Vieira, Duarte Nuno
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Artigo de Revista Científica Formato: aplication/PDF
ENG
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Clobazam (Castillium®, Urbanil®), a benzodiazepine often used as an anxiolytic and in the treatment of epilepsy, is considered a relatively safe drug. The authors present a fatal case with a 49-year-old female, found dead at home. She had been undergoing psychiatric treatment and was a chronic alcoholic. The autopsy findings were unremarkable, except for multivisceral congestion, steatosis and a small piece of a plastic blister pack in the stomach. Bronchopneumonia, bronchitis and bronchiolitis were also diagnosed. Anhigh-performance liquid chromatography (HPLC)/diode array detector (DAD)/mass spectrometry detection (MSD) with electrospray method was developed in order to detect, confirm and quantify clobazam in the post-mortem samples. In the chromatographic separation, a reversed-phase column C18 (2.1×150 mm, 3.5 [mu]m) was used with a mobile phase of methanol and water, at a 0.25 ml/min flow rate. Carbonate buffer (pH 10.5) and 20 [mu]l of prazepam (100 [mu]g/ml) as internal standard were added to the samples. A simple and reliable liquid-liquid extraction method for the determination of clobazam in post-mortem samples was described. Calibration curves for clobazam were performed in blood, achieving linearity between 0.01 and 10 [mu]g/ml and a detection limit of 1.0 ng/ml. The clobazam concentration found in post-mortem blood was 3.9 [mu]g/ml...

Determinação de hormônios estrógenos em água potável usando CLAE-DAD; Determination of estrogens in drinking water using HPLC-DAD

VERBINNEN, Raphael Teixeira; NUNES, Gilvanda Silva; VIEIRA, Eny Maria
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica
POR
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An analytical procedure for determination of estriol, 17β-estradiol, estrone and 17α-ethinylestradiol in drinking water is presented. The method employs solid phase extraction (SPE) and sample dechlorination as cleanup procedures, followed by HPLC-DAD analysis. Validation was carried out using RE No. 899/2003 guidelines established by the Agência Nacional de Vigilância Sanitária (National Agency of Sanitary Surveillance, Brazil), with some adaptations. The statistically evaluated results have shown that the method is selective, precise (0,06% to 19,40% CV) and accurate (91,52% to 109,41% average recoveries). The developed method was applied to the analysis of these contaminants in drinking water from São Luís, MA.

Online identification of chlorogenic acids, sesquiterpene lactones, and flavonoids in the Brazilian arnica Lychnophora ericoides Mart. (Asteraceae) leaves by HPLC-DAD-MS and HPLC-DAD-MS/MS and a validated HPLC-DAD method for their simultaneous analysis

GOBBO-NETO, Leonardo; LOPES, Norberto P.
Fonte: AMER CHEMICAL SOC Publicador: AMER CHEMICAL SOC
Tipo: Artigo de Revista Científica
ENG
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Lychnophora ericoides Mart. (Asteraceae, Vernonieae) is a plant, endemic to Brazil, with occurrence restricted to the ""cerrado"" biome. Traditional medicine employs alcoholic and aqueous-alcoholic preparations of leaves from this species for the treatment of wounds, inflammation, and pain. Furthermore, leaves of L. ericoides are also widely used as flavorings for the Brazilian traditional spirit ""cachaca"". A method has been developed for the extraction and HPLC-DAD analysis of the secondary metabolites of L. ericoides leaves. This analytical method was validated with 11 secondary metabolites chosen to represent the different classes and polarities of secondary metabolites occurring in L. ericoides leaves, and good responses were obtained for each validation parameter analyzed. The same HPLC analytical method was also employed for online secondary metabolite identification by HPLC-DAD-MS and HPLC-DAD-MS/MS, leading to the identification of di-C-glucosylflavones, coumaroylglucosylflavonols, flavone, flavanones, flavonols, chalcones, goyazensolide, and eremantholide-type sesquiterpene lactones and positional isomeric series of chlorogenic acids possessing caffeic and/or ferulic moieties. Among the 52 chromatographic peaks observed...

Quantification of isoorientin and total flavonoids in Passiflora edulis fruit pulp by HPLC-UV/DAD

ZERAIK, M. L.; YARIWAKE, J. H.
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
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A method is reported for the quantification of isoorientin (using a standard addition method) and total flavonoids (expressed as rutin, using the external standard method) in passion fruit pulp (Passiflora edulis Sims f. flavicarpa Degener, Passifloraceae). Extraction of flavonoids was optimized by experimental design methodology, and quantitative analysis was performed by high-performance liquid chromatography with photo-diode array detection (HPLC-UV/DAD). The method was developed and validated according to ICH requirements for specificity, linearity, accuracy, precision (repeatability and intermediate precision). LOD and LOQ. Rutin was chosen as standard for the quantification of total flavonoids in order to propose a HPLC method feasible for routine analysis of the flavonoids in the passion fruit pulp. The passion fruit pulp contained 16.226 +/- 0.050 mg L(-1) of isoorientin and 158.037 +/- 0.602 mg L(-1) of total flavonoid, suggesting that P. edulis fruits may be comparable with other flavonoid food sources such as orange juice or sugarcane juice. (C) 2010 Elsevier B.V. All rights reserved.

LC-DAD/ESI-MS/MS study of phenolic compounds in ash (Fraxinus excelsior L. and F. americana L.) heartwood. Effect of toasting intensity at cooperage

Sanz, Miriam; Fernandez de Simon, Brigida; Cadahia, Estrella; Esteruelas, Enrique; Munoz, Angel M.; Hernandez, Teresa; Estrella, Isabel; Pinto, Ernani
Fonte: WILEY-BLACKWELL; HOBOKEN Publicador: WILEY-BLACKWELL; HOBOKEN
Tipo: Artigo de Revista Científica
ENG
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The phenolic composition of heartwood extracts from Fraxinus excelsior L. and F. americana L., both before and after toasting in cooperage, was studied using LC-DAD/ESI-MS/MS. Low-molecular weight (LMW) phenolic compounds, secoiridoids, phenylethanoid glycosides, dilignols and oligolignols compounds were detected, and 48 were identified, or tentatively characterized, on the basis of their retention time, UV/Vis and MS spectra, and MS fragmentation patterns. Some LMW phenolic compounds like protocatechuic acid and aldehyde, hydroxytyrosol and tyrosol, were unlike to those for oak wood, while ellagic and gallic acid were not found. The toasting of wood resulted in a progressive increase in lignin degradation products with regard to toasting intensity. The levels of some of these compounds in medium-toasted ash woods were much higher than those normally detected in toasted oak, highlighting vanillin levels, thus a more pronounced vanilla character can be expected when using toasted ash wood in the aging wines. Moreover, in seasoned wood, we found a great variety of phenolic compounds which had not been found in oak wood, especially oleuropein, ligstroside and olivil, along with verbascoside and isoverbascoside in F. excelsior, and oleoside in F. americana. Toasting mainly provoked their degradation...

Desenvolvimento e validação de método analítico por CLAE-UV-DAD para quantificação e análise sazonal de derivados galoilquínicos nas folhas de Copaifera langsdorffii; Development and validation of analytical method by HPLC-UV-DAD for quantification and seasonal studies of galloylquinic compounds from Copaifera langsdorffii leaves.

Motta, Erick Vicente da Silva
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 24/03/2014 PT
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Copaifera langsdorffii (Fabaceae, Caesalpinioideae), conhecida popularmente como "copaíba", "copaibeira" ou "pau d'óleo", é uma árvore de grande porte que se encontra amplamente distribuída pelo Brasil, desde a floresta amazônica até a vegetação do cerrado. A oleorresina, constituída principalmente por sesquiterpenos e diterpenos, é utilizada na medicina popular no tratamento de desordens infecciosas e inflamatórias. Por outro lado, estudos sobre suas folhas, as quais são constituídas majoritariamente por flavonoides e derivados galoilquínicos, são escassos. Assim, foi proposto o isolamento de marcadores químicos, desenvolvimento e validação de método analítico por CLAE-UV-DAD, bem como o estudo sazonal. O extrato bruto obtido das folhas foi particionado com solventes de polaridade crescente: diclorometano, acetato de etila e n-butanol. As frações em n-butanol e aquosa apresentaram, majoritariamente, compostos polares, dentre os quais se destacaram os derivados galoilquínicos. Para isolamento desses compostos utilizaram-se a cromatografia de permeação em gel de Sephadex LH-20 e a cromatografia líquida de alta eficiência preparativa. Nas análises por CLAE-UV-DAD empregou-se coluna analítica Synergi Polar-RP (100 mm x 3...

DAD

Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Fotografia Formato: Foto; image/jpeg; Digital; Colorida
POR
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Prédio do DAD, abertura, janela, Campus Centro, entorno

DAD

Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Fotografia Formato: Foto; image/jpeg; Digital; Colorida
POR
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36.92%
Prédio do DAD, abetura janela, Campus Centro, entrono

DAD

Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Fotografia Formato: Foto; image/jpeg; Digital; Colorida
POR
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36.92%
Prédio do DAD, azulejos, Campus Centro, entorno

Interval multivariate curve resolution in the dereplication of HPLC-DAD data from Jatropha gossypifolia

Pilon, Alan Cesar; Carneiro, R. L.; Carnevale Neto, F.; Bolzani, Vanderlan da Silva; Castro-Gamboa, I.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 401-406
ENG
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Introduction Jatropha gossypifolia has been used quite extensively by traditional medicine for the treatment of several diseases in South America and Africa. This medicinal plant has therapeutic potential as a phytomedicine and therefore the establishment of innovative analytical methods to characterise their active components is crucial to the future development of a quality product. Objective To enhance the chromatographic resolution of HPLC-UV-diode-array detector (DAD) experiments applying chemometric tools. Methods Crude leave extracts from J. gossypifolia were analysed by HPLC-DAD. A chromatographic band deconvolution method was designed and applied using interval multivariate curve resolution by alternating least squares (MCR-ALS). Results The MCR-ALS method allowed the deconvolution from up to 117% more bands, compared with the original HPLC-DAD experiments, even in regions where the UV spectra showed high similarity. The method assisted in the dereplication of three C-glycosylflavones isomers: vitexin/isovitexin, orientin/homorientin and schaftoside/isoschaftoside. Conclusion The MCR-ALS method is shown to be a powerful tool to solve problems of chromatographic band overlapping from complex mixtures such as natural crude samples. Copyright © 2013 John Wiley & Sons...

Analysis of early synthetic dyes with HPLC-DAD-MS: an important database for analysis of colorants used in cultural heritage

Souto, Cátia Susana da Costa Nogueira
Fonte: Faculdade de Ciências e Tecnologia Publicador: Faculdade de Ciências e Tecnologia
Tipo: Dissertação de Mestrado
Publicado em //2010 ENG
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Presented thesis at Faculdade de Ciências e Tecnologias, Universidade de Lisboa, to obtain the Master Degree in Conservation and Restoration of Textiles; The analysis of 62 early synthetic dyes from the Smithsonian‟s Helmut Schweppe Collection with High Performance Liquid Chromatography – Diode Array Detection – Mass Spectrometry (HPLC-DAD-MSn) was performed. Several chromatographic and mass parameters were optimized in order to characterize the 62 dyes. This approach was also applied to selected natural dyes because early synthetic dyes were known to be dyed together with dyes from natural biological sources. Prior to the HPLC-DAD-MSn analysis, soft extraction methods were tested on dyed textiles. In the present study it was possible to characterize the 62 dyes from 11 chemical families as well as selected natural dyes using the same methodology. Also the soft extraction methods were successful in both synthetic and natural dyes recovery. This HPLC-DAD-MSn database was compared with samples from a Persian carpet, from 20th century. It was possible to conclude that the carpet was dyed with synthetic dyes. The yellow and beige colours were obtained with a mixture of azo flavine 3R (CI 13090) and orange IV (13080,) and the red colours were obtained with scarlet n for silk (CI 15635) and cotton scarlet (CI 27290). The blue colours were obtained with synthetic dyes probably from the tryarilmethane family. The green colour was obtained with a mixture of the yellow and blue synthetic dyes mentioned previously.

Study of the Degradation of the Herbicide Clomazone in Distilled and in Irrigated Rice Field Waters using HPLC-DAD and GC-MS

Zanella, Renato; Primel, Ednei Gilberto; Gonçalves, Fábio Ferreira; Martins, Manoel Leonardo; Adaime, Martha Bohrer; Marchesan, Enio; Machado, Sérgio Luiz de Oliveira
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
ENG
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Este estudo avaliou a degradação do herbicida clomazone em água destilada e de campos de arroz irrigado, através de irradiação UV e sob condições naturais. Após a etapa de pré-concentração por extração em fase sólida (SPE), a concentração remanescente foi determinada por cromatografia líquida de alta eficiência com detecção por arranjo de diodos (HPLC-DAD) e a identificação dos produtos de degradação foi efetuada por cromatografia gasosa com espectrometria de massas (GC-MS). Sob irradiação UV, o clomazone foi degradado mais rapidamente na água destilada que na água de superfície. Na água de irrigação, sob luz solar, o clomazone apresentou tempo de meia-vida médio de 3,2 dias em três safras consecutivas, e após a aplicação a concentração na água permaneceu acima de 0,1 μg L-1 por cerca de 20 dias. Diversos subprodutos, tais como 2-clorobenzaldeído e 2-clorobenzeno metanol, foram identificados por GC-MS, evidenciando que a concentração dos intermediários aumentou no início e então eles também sofreram degradação.; This study evaluated the degradation of the herbicide clomazone in distilled water and from irrigated rice fields, through UV irradiation and under natural conditions. After a solid phase extraction (SPE) as preconcentration step...

Avoiding DAD for Improving Real-Time Communication in MIPv6 Environments

Bagnulo, Marcelo; Soto, Ignacio; García-Martínez, Alberto; Azcorra, Arturo
Fonte: Springer Publicador: Springer
Tipo: Conferência ou Objeto de Conferência Formato: application/pdf
Publicado em /10/2002 ENG
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Current specification of address configuration mandates the execution of the Duplicate Address Detection (DAD) mechanism to prevent address duplication. However, a proper support for real time multimedia applications in mobile IPv6 nodes is undermined by the disruption imposed by DAD. In order to overcome this limitation, the usage of randomly generated IPv6 Interface Identifiers without previously performing DAD is proposed, based on the statistic uniqueness of the addresses generated through this method. The address duplication risk is quantified through the calculation of the probability of an Interface Identifier collision among the nodes sharing a link. The calculated probability is deemed to be negligible compared to other causes of communication failure, such as network outages.; This research was supported by the LONG (Laboratories Over Next Generation Networks) project IST-1999-20393 and Moby Dick (Mobility and Differentiated Services in a Future IP Network) project IST-2000-25394.; Joint International Workshops on Interactive Distributed Multimedia Systems and Protocols for Multimedia Systems, IDMS/PROMS 2002 Coimbra, Portugal, November 26–29, 2002 Proceedings

HPLC-DAD-MS/MS profiling of phenolics from Securigera securidaca flowers and its anti-hyperglycemic and anti-hyperlipidemic activities

Ibrahim,Rana M.; El-Halawany,Ali M.; Saleh,Dalia O.; El Naggar,El Moataz Bellah; El-Shabrawy,Abd El-Rahman O.; El-Hawary,Seham S.
Fonte: Sociedade Brasileira de Farmacognosia Publicador: Sociedade Brasileira de Farmacognosia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2015 EN
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Abstract Securigera securidaca (L.) Degen & Döefl., Fabaceae, has been widely used in the Iranian, Indian and Egyptian folk medicine as antidiabetic and anti-hyperlipidemic remedy. Phenolic profiling of the ethanolic extract (90%) of the flowers of S. securidaca was performed via HPLC-DAD-MS/MS analysis in the positive and negative ion modes. The total polyphenols and flavonoids in the flowers were determined colorimetrically, and the quantification of their components was carried out using HPLC-UV. Total phenolics and flavonoids estimated as gallic acid and rutin equivalents were 82.39 ± 2.79 mg/g and 48.82 ± 1.95 mg/g of the dried powdered flowers, respectively. HPLC-DAD-MS/MS analysis of the extract allowed the identification of 39 flavonoids and eight phenolic acids. Quantitative analysis of some flavonoids and phenolics (mg/100 g powdered flowers) revealed the presence of isoquercetrin (3340 ± 2.1), hesperidin (32.09 ± 2.28), naringin (197.3 ± 30.16), luteolin (10.247 ± 0.594), chlorogenic acid (84.22 ± 2.08), catechin (3.94 ± 0.57) and protocatechuic acid (34.4 ± 0.15), in the extract. Moreover, the acute toxicity, hypoglycemic and hypolipidemic effects of the extract were investigated using alloxan induced diabetes in rats in a dose of 100...

\"Desenvolvimento de metodologia analítica para a determinação de hidrocarbonetos policíclicos aromáticos (PAHs) em amostras de água utilizando uma interface SPME/HPLC/DAD\"; \"Development of an analytical methodology for polycyclic aromatic hydrocarbons (PAH\'s) analysis in water samples using a SPME/LC/DAD interface\"

Ferreira, Fernanda Cristine Spoljaric
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 20/03/2006 PT
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Este trabalho descreve a otimização e validação de um método analítico para a análise de hidrocarbonetos policíclicos aromáticos (PAHs) em água usando uma interface SPME/LC/DAD. Parâmetros como tipos de fibra, tempo de extração, temperatura e força iônica foram estudados no modo \"off line\" e a influência destes na eficiência de extração foi avaliada. Os melhores resultados foram obtidos com a fibra Carbowax/templeted resin. Uma interface \"lab made\" foi utilizada para a etapa de validação e as curvas de calibração mostraram boa linearidade (r>0,99) para a maioria dos compostos analisados, tanto na linearidade da amostra como na linearidade do padrão. Os dados de precisão obtidos na concentração de trabalho variaram de 1 a 3%, aproximadamente, e os valores de recuperação se mantiveram na faixa de 4 a 27%. Os PAHs foram determinados na faixa de 0,025 micro g até 0,5 micro g. Pode-se considerar os valores obtidos nos itens de precisão e linearidade satisfatórios para a análise dos PAHs, considerando-se os critérios internacionais estabelecidos para esta classe de compostos, mas o método não atende as especificações relacionadas a recuperação e faixa de concentração.; This work describes the optimization and validation of an analytical method to determine Polycyclic Aromatic Hydrocarbons (PAHs) in water using a SPME/LC/DAD interface. Parameters as fibers kind...

Separation and characterization of antioxidants from Spirulina platensis microalgacombining pressurized liquid extraction, TLC and HPLC-DAD

Jaime, Laura; Mendiola León, Jose Antonio; Herrero, Miguel; Soler-Rivas, Cristina; Santoyo, Susana; Señorans, F. Javier; Cifuentes, Alejandro; Ibáñez, Elena
Fonte: Wiley-VCH Publicador: Wiley-VCH
Tipo: Artículo Formato: 818700 bytes; application/pdf
ENG
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A new procedure has been developed to separate and characterize antioxidant compounds from Spirulina platensis microalga based on the combination of pressurized liquid extraction (PLE) and different chromatographic procedures, such as Thin-Layer Chromatography (TLC), at preparative scale, and High Performance Liquid Chromatography (HPLC) with a Diode Array Detector (DAD). Different solvents were tested for PLE extraction of antioxidants from Spirulina platensis microalga. An optimized pressurized liquid extraction process using ethanol (generally recognized as safe, GRAS) as extraction solvent has been obtained that provides natural extracts with high yields and good antioxidant properties. TLC analysis of this ethanolic extract obtained at 115°C for 15 min was carried out and the silica layer was stained with a DPPH• (diphenyl-pycril-hydrazyl) radical solution to determine the antioxidant activity of the different chromatographic bands. Next, these coloured bands were collected for their subsequent analysis by HPLC-DAD revealing that the compounds with the most important antioxidant activity present in Spirulina extracts were carotenoids, as well as phenolic compounds and degradation products of chlorophylls.; JAM and MH thank MCYT for FPI grants. Authors thank MCYT (project AGL2002-04621- C02-02) for financial support.; Peer reviewed

QuEChERS-HPLC-DAD method for sulphonamides in chicken breast

Machado, Simone Caetani; Landin-Silva, Mariane; Maia, Patrícia Penido; Rath, Susanne; Martins, Isarita
Fonte: Universidade de São Paulo. Faculdade de Ciências Farmacêuticas Publicador: Universidade de São Paulo. Faculdade de Ciências Farmacêuticas
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; ; Formato: application/pdf
Publicado em 01/03/2013 ENG
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O desenvolvimento de um método QuEChERS-HPLC-DAD usando uma coluna Lichrospher RP-60 Select B (250 x 4,6 mm x 5 µm) a 40 ºC, fase móvel constituída por tampão de fosfato: acetonitrila (75:25, v/v) a uma vazão inicial de 0,5 mL min-1, aumentando 1,2 mL min-1 e a 265 nm é apresentado para a determinação simultânea de sulfadiazina, sulfametoxipiridazina e sulfametoxazol em amostras de peito de frango. O QuEChERS é barato, rápido e fácil, e a extração dos analitos da matriz foi empregada com sucesso. Além disso, o método apresentou linearidade, na faixa de 25, 50, 100, 150, 175 e 200 µg kg-1, precisão, seletividade e sensibilidade. A precisão intradia (RSD %) para o método QuEChERS foi entre 3,6-10,8 (SDZ), 6,9-14,1 (SPZ) e 1,9-10,9 (SMX) e a precisão interdias (RSD%) foi entre 1,5-9,7, 1,7-4,1 e 2,1-10,1, respectivamente. Resultados de exatidão (tendenciosidade) foram na faixa de -8,6 a +11,9%. Portanto, o método validado é útil para a monitorização de resíduos de medicamentos avaliados em amostras de frangos, bem como todos os valores estavam dentro dos critérios aceitáveis utilizados para a segurança dos alimentos. De seis amostras analisadas, nenhuma apresentou contaminação de sulfonamidas nos níveis detectáveis estudados.; The development of a QuEChERS-HPLC-DAD method using a Lichrospher 60 RP-Select B column (250 x 4.6 mm x 5 µm) at 40ºC...