974 resultados para Hplc-ms


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Pea-shoots are a new option as ready-to-eat baby-leaf vegetable. However, data about the nutritional composition and the shelf-life stability of these leaves, especially their phytonutrient composition is scarce. In this work, the macronutrient, micronutrient and phytonutrients profile of minimally processed pea shoots were evaluated at the beginning and at the end of a 10-day storage period. Several physicochemical characteristics (color, pH, total soluble solids, and total titratable acidity) were also monitored. Standard AOAC methods were applied in the nutritional value evaluation, while chromatographic methods with UV–vis and mass detection were used to analyze free forms of vitamins (HPLC-DAD-ESI-MS/MS), carotenoids (HPLC-DAD-APCI-MSn) and flavonoid compounds (HPLC-DAD-ESI-MSn). Atomic absorption spectrometry (HR-CS-AAS) was employed to characterize the mineral content of the leaves. As expected, pea leaves had a high water (91.5%) and low fat (0.3%) and carbohydrate (1.9%) contents, being a good source of dietary fiber (2.1%). Pea shoots showed a high content of vitamins C, E and A, potassium and phosphorous compared to other ready-to-eat green leafy vegetables. The carotenoid profile revealed a high content of β-carotene and lutein, typical from green leafy vegetables. The leaves had a mean flavonoid content of 329 mg/100 g of fresh product, mainly composed by glycosylated quercetin and kaempferol derivatives. Pea shoots kept their fresh appearance during the storage being color maintained throughout the shelf-life. The nutritional composition was in general stable during storage, showing some significant (p < 0.05) variation in certain water-soluble vitamins.

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This study analysed 22 strawberry and soil samples after their collection over the course of 2 years to compare the residue profiles from organic farming with integrated pest management practices in Portugal. For sample preparation, we used the citrate-buffered version of the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. We applied three different methods for analysis: (1) 27 pesticides were targeted using LC-MS/MS; (2) 143 were targeted using low pressure GC-tandem mass spectrometry (LP-GC-MS/MS); and (3) more than 600 pesticides were screened in a targeted and untargeted approach using comprehensive, two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOF-MS). Comparison was made of the analyses using the different methods for the shared samples. The results were similar, thereby providing satisfactory confirmation of both similarly positive and negative findings. No pesticides were found in the organic-farmed samples. In samples from integrated pest management practices, nine pesticides were determined and confirmed to be present, ranging from 2 μg kg−1 for fluazifop-pbutyl to 50 μg kg−1 for fenpropathrin. Concentrations of residues in strawberries were less than European maximum residue limits.

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Dissertação apresentada para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Arqueologia

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An analytical methodology for the simultaneous determination of seven pharmaceuticals and two metabolites belonging to the non-steroidal anti-inflammatory drugs (NSAIDs) and analgesics therapeutic groups was developed based on off-line solid-phase extraction and ultra-high performance liquid chromatography coupled to tandem mass spectrometry (SPE–UHPLC–MS/MS). Extraction conditions were optimized taking into account parameters like sorbent material, sample volume and sample pH. Method detection limits (MDLs) ranging from 0.02 to 8.18 ng/L were obtained. This methodology was successfully applied to the determination of the selected pharmaceuticals in seawater samples of Atlantic Ocean in the Northern Portuguese coast. All the pharmaceuticals have been detected in the seawater samples, with pharmaceuticals like ibuprofen, acetaminophen, ketoprofen and the metabolite hydroxyibuprofen being the most frequently detected at concentrations that can reach some hundreds of ng/L.

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The phenolic profile and antioxidant activity of three endemic Laurus sp. from Portugal were analysed. Dried leaves of L. nobilis L., L. azorica (Seub.) Franco, and L. novocanariensis Rivas Mart., Lousã, Fern. Prieto, E. Días, J. C. Costa & C. Aguiar, collected in the mainland and in the Azores and Madeira archipelagos, respectively, were used to prepare different extracts (aqueous, ethanolic and hydroalcoholic). They were studied regarding their DPPH˙ scavenging activity, total phenolic and flavonoid contents, and the main phenolic compounds were identified by HPLC-DAD-ESI-MS/MS. Total flavonoid contents were 30.1, 46.3, and 36.7 mg of epicatechin equivalents per g of sample (dry weight) for L. nobilis, L. azorica and L. novocanariensis, respectively. Epicatechin was the major compound, representing ∼12.1% of total flavan-3-ols in L. nobilis, ∼25.6% in L. azorica, and ∼19.9% in L. novocanariensis. Although all samples presented a similar phenolic profile, significant differences were observed in their total contents and antioxidant activity.

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Synthetic pyrethroids are pesticides derived from naturally occurring pyrethrins, taken from pyrethrum of dried Chrysanthemum flowers. Pyrethroid insecticides are one of the most commonly used residential and agricultural insecticides. Many pyrethroids can significantly harm the nervous system. Permethrin could be one of the factors involved in the onset of neurodegenerative diseases. The present study aims to evaluate in brain, the effect that can induce the exposure to permethrin, during early life of female rats (from 6 to 21 days of life). Therefore, have been examined the concentrations of permethrin and its main metabolite (3-PBA) in the brain and urine in female rats sacrificed the day after and 14 days after treating. The different concentrations of permethrin and 3-PBA (after 24h and after 14 days in the end of treatment) were obtained using two different methods. The evaluation of permethrin by liquid-liquid extraction and GC-ECD was performed. The levels of the 3-PBA (in urine and brains) were obtained by SPE procedure and GC-MS using the 2- PBA as internal standard.

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o trabalho nomográfico desenvolvido por Alexandra Leal Barradas, centrado no mecenatismo do 4.° conde de Ourem, e, de alguma forma, pioneiro na sua área, vindo preencher uma enorme lacuna no âmbito destes estudo s de Historia da Arte. Torna-se imperioso, em meu entender; avançar paulatinamente nestes domínios, explorando com segurança estes promissores campos de investigação. Este, afinal, 0 caso do presente livro, uma monografia resultante da dissertação de Mestrado em História da Arte apresentada na Faculdade de Ciências Sociais e Humanas. Em boa hora, a autora aceitou a sugestão e 0 desafio que lhe lancei.

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RESUMO: Introdução e objetivos: Não existia um estudo multicêntrico que descrevesse as características dos doentes com EM, da doença em si, ou do seu tratamento, em Portugal.Métodos: Doentes McDonald 2010 positivos foram sequencialmente recrutados em 7 centros entre Maio e Novembro 2014. Aplicou-se um Caderno de Recolha de Dados incidindo na demografia, doença, educação e emprego (estudo PORT-MS). Resultados: 561 doentes incluídos. Primeiros sintomas aos 30,2±10,5 anos (RRMS 29,2±10, PPMS 39,4±11,7, p<0,001); diagnóstico 3,2±5,3 anos depois (RRMS 3,0±5,1, PPMS 4,9±2,5, p=0,002); tempo de doença após diagnóstico 9,4±7,2 anos (semelhante RRMS no diagnóstico e PPMS); idade atual 42,9±12,4 anos (grupo RRMS no diagnóstico 42,0±12,1, PPMS 52,5±11,3, p<0,001); EDSS atual 2,5 (RRMS 2.0, PPMS 6.0); proporção feminino:masculino é 2,5:1 (RRMS semelhante, PPMS 1,1:1, p<0,05); no diagnóstico RRMS 90,6%, SPMS 0,9%, PPMS 8,6%; 9,5% dos RRMS encontravam-se em SP na inclusão (nomeadamente os com mais idade no diagnóstico e/ou atualidade ou tempo de doença mais prolongado). PPMS mais frequente em doentes diagnosticados mais tardiamente (p<0,001), onde aumenta também ligeiramente a proporção de mulheres na PPMS. Nas últimas décadas: novos casos mostram estabilidade na proporção de géneros e tipos de doença; idade nos primeiros sintomas e no diagnóstico aumentou ligeiramente, tempo entre eles diminuiu ligeiramente. Proporção sob DMT (Maio 2014): global 84,5%; atualmente RRMS 90,4%; SPMS 70,8%; PPMS 36,8%; progressivas agregadas 48%. Tipo de DMT, amostra global: interferões 56,5%, GA 18,4%, Natalizumab 11,6%, Fingolimod 9,7%. Global: economicamente ativos 61,5%, desemprego 13,5%, 74,1% dos não activos estão reformados por doença. Gravidezes após diagnóstico em 15% mulheres. Casos com história familiar positiva 7,8%. Discussão e conclusões: Incluída cerca de 10% da população portuguesa. Resultados congruentes com dados internacionais. Elevada proporção sob DMT, mesmo EDSS alto e formas progressivas. Terapêuticas de segunda linha sub representadas. Doentes jovens e com doença ligeira com vida económica ativa; restantes essencialmente reformados por doença.---------------- ABSTRACT : Background/aims: In Portugal, there wasn’t a multicentric study on the general characteristics (demography, disease milestones, DMT, socioeconomic status) of Multiple Sclerosis patients. Methods: Patients fulfilling McDonald 2010 criteria were sequentially recruited from May to November 2014 in 7 centers and data was systematically collected. Results: 561 patients included. First symptoms occurred at 30,2±10,5 years-old (RRMS 29,2±10, PPMS 39,4±11,7, p<0,001); diagnosis 3,2±5,3 years later (RRMS 3,0±5,1, PPMS 4,9±2,5, p=0,002); 9,4±7,2 years elapsed since diagnosis (similar for those is RRMS at diagnosis and PPMS); current age 42,9±12,4 years-old (group RRMS at diagnosis 42,0±12,1, PPMS 52,5±11,3, p<0,001); current EDSS 2,5 (RRMS 2.0, PPMS 6.0); females to males 2,5:1 (RRMS similar, PPMS 1,1:1, p<0,05); at diagnosis RRMS 90,6%, SPMS 0,9%, PPMS 8,6%; 9,5% of RRMS reached SP at inclusion (those older at diagnosis, in actuality, or with longer follow-up). PPMS more frequente in patients diagnosed at older ages (p<0,001), also slight increase in females. Along the last decades: new cases have showed stable proportions of gender and disease types; age at first symptoms and diagnosis slightly increased, time between them slightly decreased. Proportion on DMT (May 2014): 84,5% of all; 90,4% of currently in RRMS; 70,8% of SPMS; 36,8% of PPMS; 48% of progressive forms together. Type of DMT, all patients: interferons 56,5%, Glatiramer Acetate 18,4%, Natalizumab 11,6%, Fingolimod 9,7%. Economically active 61,5% of all, unemployment 13,5%, 74,1% of non-active are retired due to disease. Females pregnant after diagnosis 15%. Positive family cases in 7,8%. Discussion/Conclusions: 10% of the national MS population collected. Data generally consistente with international reports. Proportion under DMT relatively high in all disease types, but second line therapies underrepresented. Young patients with mild disease have an active economic life. Those not active are essentially retired due to disease.

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Captan and folpet are fungicides largely used in agriculture. They have similar chemical structures, except that folpet has an aromatic ring unlike captan. Their half-lives in blood are very short, given that they are readily broken down to tetrahydrophthalimide (THPI) and phthalimide (PI), respectively. Few authors measured these biomarkers in plasma or urine, and analysis was conducted either by gas chromatography coupled to mass spectrometry or liquid chromatography with UV detection. The objective of this study was thus to develop simple, sensitive and specific liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry (LC/APCI-MS/MS) methods to quantify both THPI and PI in human plasma and urine. Briefly, deuterated THPI was added as an internal standard and purification was performed by solid-phase extraction followed by LC/APCI-MS/MS analysis in negative ion mode for both compounds. Validation of the methods was conducted using spiked blank plasma and urine samples at concentrations ranging from 1 to 250 μg/L and 1 to 50 μg/L, respectively, along with samples of volunteers and workers exposed to captan or folpet. The methods showed a good linearity (R (2) > 0.99), recovery (on average 90% for THPI and 75% for PI), intra- and inter-day precision (RSD, <15%) and accuracy (<20%), and stability. The limit of detection was 0.58 μg/L in urine and 1.47 μg/L in plasma for THPI and 1.14 and 2.17 μg/L, respectively, for PI. The described methods proved to be accurate and suitable to determine the toxicokinetics of both metabolites in human plasma and urine.

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Gas chromatography (GC) is an analytical tool very useful to investigate the composition of gaseous mixtures. The different gases are separated by specific columns but, if hydrogen (H2 ) is present in the sample, its detection can be performed by a thermal conductivity detector or a helium ionization detector. Indeed, coupled to GC, no other detector can perform this detection except the expensive atomic emission detector. Based on the detection and analysis of H2 isotopes by low-pressure chemical ionization mass spectrometry (MS), a new method for H2 detection by GC coupled to MS with an electron ionization ion source and a quadrupole analyser is presented. The presence of H2 in a gaseous mixture could easily be put in evidence by the monitoring of the molecular ion of the protonated carrier gas. Copyright © 2013 John Wiley & Sons, Ltd.

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Drug abuse is a widespread problem affecting both teenagers and adults. Nitrous oxide is becoming increasingly popular as an inhalation drug, causing harmful neurological and hematological effects. Some gas chromatography-mass spectrometry (GC-MS) methods for nitrous oxide measurement have been previously described. The main drawbacks of these methods include a lack of sensitivity for forensic applications; including an inability to quantitatively determine the concentration of gas present. The following study provides a validated method using HS-GC-MS which incorporates hydrogen sulfide as a suitable internal standard allowing the quantification of nitrous oxide. Upon analysis, sample and internal standard have similar retention times and are eluted quickly from the molecular sieve 5Å PLOT capillary column and the Porabond Q column therefore providing rapid data collection whilst preserving well defined peaks. After validation, the method has been applied to a real case of N2O intoxication indicating concentrations in a mono-intoxication.

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Die Differenzierung von Tinten erweist sich oft als wichtig in der Echtheitsprüfung von Dokumenten. Sie wird üblicherweise durch optische Vergleiche und Dünnschicht Chromatographie durchgeführt (TLC). Laser Desorption Ionisation Massenspektrometrie (LDI-MS) ist auch als nützlich gefunden worden und besonders leistungsfähig um Farbstoffe aus Kugelschreibertinte zu analysieren. Diese analytische Methode ist mit Hochleistungs Dünnschichtchromatografie TLC (HPTLC) verglichen worden, mit dem Ziel deren Tinten-Differenzierungskapazität zu testen. Tinteneinträge von 31 blauen Kugelschreibern sind analysiert worden und gemäß deren Farbstoffzusammensetzung klassifiziert worden. Typische Farbstoffe sind durch beide Methoden identifiziert worden und mehrere sind in vielen Tinten-Zusammensetzungen gefunden worden. LDI-MS ist leistungsfähiger als HPTLC um Tinten zu differenzieren, weil es Informationen über Farbstoffstrukturen (Molekular Gewicht) enthält und eine präzise relative Quantifizierung (Signalfläche) erlaubt. Dazu ist für LDI-MS Proben die Vorbereitung minimal und die Analysezeit kurz im Vergleich zu HPTLC mehr komplexen Schritte, wie Extraktionen, Spots Applikationen und Lösungsmittelelution. Allerdings sind mit LDI-MS zwei Analysen nötig um kationische und anionische Farbstoffe zu analysieren, während mit HPTLC nur eine Analyse nötig ist.

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Background: Infection with EBV and a lack in vitamin D may be important environmental triggers of MS. 1,25-(OH)2D3 mediates a shift of antigen presenting cells (APC) and CD4+ T cells to a less inflammatory profile. Although CD8+ T cells do express the vitamin D receptor, a direct effect of 1,25(OH)2D3 on these cells has not been demonstrated until now. Since CD8+ T cells are important immune mediators of the inflammatory response in MS, we examined whether vitamin D directly affects the CD8+ T cell response, and more specifically if it modulates the EBV-specific CD8+ T cell response. Material and Methods: To explore whether the vitamin D status may influence the pattern of the EBV-specific CD8+ T cell response, PBMC of 10 patients with early MS and 10 healthy controls (HC) were stimulated with a pool of immunodominant 8-10 mer peptide epitopes known to elicit CD8+ T cell responses. PBMC were stimulated with this EBV CD8 peptide pool, medium (negative control) or anti- CD3/anti-CD28 beads (positive control). The following assays were performed: ELISPOT to assess the secretion of IFN-gamma by T cells in general; cytometric beads array (CBA) and ELISA to determine whichcytokines were released by EBV-specific CD8+ T cells after six days of culture; and intracellular cytokine staining assay to determine by which subtype of T cells secreted given cytokines. To examine whether vitamin D could directly modulate CD8+ T cell immune responses, we depleted CD4+ T cells using negative selection. Results: We found that pre-treatment of vitamin D had an antiinflammatory action on both EBV-specific CD8+ T cells and on CD3/ CD28-stimulated T cells: secretion of pro-inflammatory cytokines (IFNgamma and TNF-alpha) was decreased, whereas secretion of antiinflammatory cytokines (IL-5 and TGF-beta) was increased. At baseline, CD8+ T cells of early MS patients showed a higher secretion of TNFalpha and lower secretion of IL-5. Addition of vitamin D did not restore the same levels of both cytokines as compared to HC. Vitamin D-pretreated CD8+T cells exhibited a decreased secretion of IFN-gamma and TNF-alpha, even after depletion of CD4+ T cells from culture. Conclusion: Vitamin D has a direct anti-inflammatory effect on CD8+ T cells independently from CD4+ T cells. CD8+ T cells of patients with earlyMS are less responsive to the inflammatory effect of vitamin D than HC, pointing toward an intrinsic dysregulation of CD8+ T cells. The modulation of EBV-specific CD8+T cells by vitaminDsuggests that there may be interplay between these twomajor environmental factors of MS. This study was supported by a grant from the Swiss National Foundation (PP00P3-124893), and by an unrestricted research grant from Bayer to RDP.

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Se efectuó un muestreo sistemático paralelo en sentido perpendicular a la cota hasta las 100 y 120 mn. Las área de distribución se realizaron con el programa SURFER. La anchoveta peruana mantuvo predominio en aguas costeras y se registró hasta las 88 mn. Con amplia distribución entre Punta Falsa y el Callao.

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Para efectuar el siguiente estudio se utilizó la técnica hidroacústica, se estimaron las biomasas de onces especies.