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Determination of low molecular weight volatiles in Ficus carica using HS-SPME and GC/FID

Oliveira, A.P.; Silva, L.R.; Andrade, P.B.; Valentão, P.; Silva, B.M.; Pereira, J.A.; Pinho, P. Guedes de
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.89%
Ficus carica L. is one of the earliest cultivated fruit trees, having an important consumption in Mediterranean countries. In this work, the volatile compound profiles of two characteristic Portuguese white varieties (‘‘Pingo de Mel” and ‘‘Branca Tradicional”) was determined by HS-SPME and GC/FID. Leaves, pulps and peels, submitted to freezing and lyophilisation treatments, were analysed. The two varieties presented a similar profile composed of eight volatile compounds: acetaldehyde, ethyl acetate, methanol, ethanol, hexanal, limonene, (E)-2-hexenal and octanal. The total volatile content was different among the vegetal materials, following the order leaves > peels > pulps. Methanol and ethanol are the major compounds in all samples. The developed procedure revealed to be rapid, sensitive, reproducible and accurate. The detection limit values were low, and the method precise. The recovery values for acetaldehyde, ethyl acetate, methanol and ethanol were generally high, suggesting that it will be most suitable for compounds with low molecular weight. Due to its rapidity and low cost, this technique can be useful in the quality control of fig fruit and leaves.

Volatile biomarkers for wild mushrooms species discrimination

Malheiro, R.; Pinho, P. Guedes de; Soares, Sandra; Ferreira, António César da Silva; Baptista, Paula
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.89%
Secondary metabolites present in the volatile fraction of six wild mushroom species (Clitocybe odora, Clitocybe fragrans, Hebeloma crustuliniforme, Lepista nuda, Tricholoma fracticum and Tricholoma terreum) were studied, as an attempt to identify compounds capable to distinguish mushroom species for taxonomic and authentication purposes. Volatiles were assessed by headspace solid phase microextraction (HS–SPME) and by gas chromatography/ion-trap mass-spectrometry (GC/IT–MS). By using target analysis, 46 volatiles were grouped in 5 chemical classes: alcohols, aldehydes, ketones, sesquiterpene-like compounds and terpenes. Each species revealed a unique volatile profile, with changes in the dominant chemical class. Aliphatic compounds with eight carbon atoms, such as 3-octanol, 1-octanol and 3-octanone were the most abundant. The non-target approach application, using all HS–SPME–GC–MS data (raw chromatograms) aims to detect a large number of compounds to get a fingerprint of each sample. This procedure, involving previous data treatments as chromatogram data alignments, sample data fingerprints, and multivariate analysis, represents a powerful tool to execute an initial screening of the analytical results, enabling a faster interpretability of the results without time-consuming through identifications and quantifications. Unsupervised signal decomposition techniques such as principal component analysis (PCA) applied both to targeted and non-targeted approaches revealed 11 volatile compounds (3-octanol...

"Desenvolvimento, otimização e validação da técnica HS-SPME-GC/MS para análise de amostras obtidas do Rio Atibaia através da aplicação de uma sistemática "ISO" para diagnóstico ambiental de áreas contaminadas"; "Development, optimization and validation of HS-SPME-GC/MS method for analysis of samples gotten from Atibaia River through the application of systematic "ISO" for environmental diagnosis of contamined areas"

Olivares, Igor Renato Bertoni
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 18/12/2006 PT
Relevância na Pesquisa
57.13%
Neste trabalho foi desenvolvida, otimizada, e validada, uma metodologia para análise de 15 pesticidas organoclorados em sedimento através de HS/SPME-GC/MS. Esta metodologia foi aplicada para análise de amostras reais visando à realização de um diagnóstico da contaminação por pesticidas organoclorados do Rio Atibaia, principalmente em sua região próxima a contaminação oriunda da empresa Shell Brasil S.A. unidade de Paulínia. Para realização deste diagnóstico, também foi desenvolvida uma metodologia padronizada para diagnóstico ambiental de áreas contaminadas, embasada principalmente em conceitos de Gestão de Qualidade e Meio Ambiente abordadas nas normas ISO 17025, ISO 14001 e GLP. Finalmente, aplicando a metodologia analítica validada, e a metodologia para realização de um diagnóstico ambiental, foi realizado o diagnóstico da presença de pesticidas organoclorados no Rio Atibaia, indicando a existência de diferentes pesticidas organoclorados em sedimento, com destaque para os compostos DDE e BHC que se encontraram em valores acima dos recomendados pela legislação canadense. Os resultados encontrados também demonstraram que as metodologias desenvolvidas foram adequadas para análise de uma contaminação real.; In this work a methodology was developed...

Desenvolvimento e aplicação de método analítico para determinação de ésteres etílicos de ácidos graxos (bioindicadores do etanol) em amostras de mecônio; Development and application of an analytical method for the determination of fatty acid ethyl esters (biomarkers of ethanol) in meconium samples

Roehsig, Marli
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 28/08/2009 PT
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47.04%
O álcool é uma das substâncias psicoativas mais consumidas mundialmente e seu uso por mulheres em idade reprodutiva, em particular, tem representado grande preocupação por parte de especialistas e da sociedade em geral. Apesar dos efeitos adversos associados ao ato de ingerir bebidas alcoólicas durante a gestação ser bastante documentados e conhecidos, sabe-se que uma parcela de mulheres grávidas tem dificuldades em abandonar o hábito. O consumo excessivo de álcool durante a gravidez tem sido associado com a síndrome fetal pelo álcool (FAS), caracterizada por crianças com dificuldades comportamentais e de aprendizado. Entretanto, devido ao sentimento de culpa e medo de ações punitivas, mulheres raramente admitem terem utilizado álcool durante a gestação. Como resultado, uma série de marcadores biológicos tem sido estudada para se diagnosticar a exposição fetal ao etanol. Dentre os marcadores utilizados estão os ésteres etílicos de ácidos graxos (FAEE), que podem ser detectados em amostras de mecônio de recém-nascidos. No presente trabalho, um método analítico foi desenvolvido visando a detecção de oito FAEEs em amostras de mecônio e aplicada em amostras coletadas de recém-nascidos cujas mães admitiram ou não o uso de etanol durante a gestação. A microextração em fase sólida por Headspace (HS-SPME)...

Variabilidade temporal e intraespecífica dos constituintes voláteis das folhas de Lychnophora ericoides Mart.; Time-scale and intraspecifc variability of Lychnophora ericoides Mart. leaves volatile constituents

Pavarini, Daniel Petinatti
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 23/02/2011 PT
Relevância na Pesquisa
47.21%
A literatura relata variações espaciais e rítmicas para diferentes classes de metabólitos secundários, entretanto os dados são consistentes apenas para espécies que ocorrem em áreas temperadas. Lychnophora ericoides Mart. tem sido muito empregada popularmente como antiinflamatório e analgésico. É relatado o uso de suas partes aéreas pela população que vive nas proximidades de seu habitat em tratamentos de lesões cutâneas. L. eriocides representa uma das várias espécies da família Asteraceae endêmicas ao cerrado que biossintetizam uma ampla gama de terpenoides. Embora pouco estudada, sabe-se que a fração volátil de suas partes aéreas apresenta constituição terpênica. O presente estudo tem como objetivo determinar a constituição química desta fração volátil por meio de técnicas brandas de pré-concentração dos analitos e avaliar a variabilidade química desta fração a nível intraespecífico e temporal. Dessa forma, as coletas foram realizadas durante um período de 15 meses e utilizou-se HSSPME e CG-EM para avaliar as amostras coletadas. Um método para pré-concentração dos compostos voláteis (COVs) foi desenvolvido a partir da otimização dos parâmetros para obtenção do equilíbrio termodinâmico em HS-SPME. A obtenção de cromatogramas...

Investigação multidisciplinar da biossíntese de sesquiterpenos bioativos de Lychnophora ericoides (Vernonieae: Asteraceae); Multilevel investigation of bioactive sesquiterpene biosynthesis from Lychnophora ericoides (Vernonieae: Asteraceae)

Pavarini, Daniel Petinatti
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 29/09/2014 PT
Relevância na Pesquisa
47.17%
Lychnophora (Vernonieae: Asteraceae) é um gênero micro-endêmico dos "campus rupestris" do bioma Cerrado. Os extratos foliares de Lychnophora ericoides ("Arnica-da-serra") são usados na terapêutica popular principalmente como analgésico. Seus óleos essenciais são quimicamente ricos em sesquiterpenos. Tais compostos, principalmente os de esqueletos bisabolano e cadinano são produtos biossintéticos do precursor cátion nerolidila. Óleos essenciais de folhas de L. ericoides são bioativos frente a invertebrados do Táxon Acari. Um de seus componentes majoritários, o orto-acetoxi bisabolol, é antinociceptivo em ensaios in vitro. Terpenos são valorizados pela indústria de química fina, haja vista sucessos como Taxol® e Acheflan®. Nossos objetivos em Fitoquímica e Ciências Farmacêuticas se alinham a esse interesse. As terpeno-sintases (TerpS) envolvidas na biossínteses dos compostos são ainda alvo de pesquisas com em Bioquímica. Sua identificação é frequentemente conclusiva em diversos aspectos. Como exemplo, citamos a compreensão dos mecanismos da variabilidade metabólica temporal em espécies nativas e selvagens e os avanços na bioengenharia de Produtos Naturais (PN). Frente a este cenário de fronteira este manuscrito traz um resumo da investigação que objetivou determinar se há diversas isoformas de TerpS operando na produção temporalmente variável de sesquiterpenos bioativos em tecidos foliares de Lychnophora ericoides ou se não as há. Acessamos diferentes amostras selvagens de L. ericoides in situ. Nossos esforços em responder a questão supracitada foram divididos em tarefas...

Estudo dos compostos voláteis de algumas espécies de eucalipto através do uso de microextração em fase sólida no modo headspace (HS-SPME)

Zini, Claudia Alcaraz
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Tese de Doutorado Formato: application/pdf
POR
Relevância na Pesquisa
46.89%
Neste trabalho utilizou-se a técnica de HS-SPME/GC/ITMS para o estudo qualitativo dos compostos voláteis (VOC) emitidos pelas folhas de três espécies de Eucalyptus (E.): E. citriodora, E. dunnii e E. saligna tanto em laboratório como in situ, além do estudo da relação entre folhas de eucalipto e rãs Litoria ewingi. Para este fim, foram desenvolvidos métodos análiticos. Os compostos tentativamente como (E,E)-a-farseno, (E)-4,8-dimetil-1,3,7-nonatrieno (DMNT),(E,E)-4,8,12-trimetil-1,3,7,11-tridecatetraeno (TMTT),B-cariofileno,a-cariofileno, gerrmacreno D e (E,E,E)-3,7,11,15-tetrametil-1,3,6,10,14-hexadecapentaeno (TMHP) foram encontrados no headspace de folhas picadas de eucalipto, sendo que os três primeiros também foram nas emissões áreas de E. saligna in situ, não tendo sido encontrados nos óleos voláteis das mesmas árvores, obtidos por hidrodestilação. Nas amostragens in situ, foram observados dois tipos de perfis circadianos nas emissões voláteis, incluindo compostos como cis-, trans-óxido de rosa, trans-B-ocimeno, citronelal, citronelol, entre outros. O comportamento dos compostos citados sugere que os mesmos sejam semioquímicos. Os resultados obtidos com HS-SPME (PDMS/DVB) mostraram que esta é uma ferramenta analítica relativamente simples...

The Use of Headspace Solid-Phase Microextraction (HS-SPME) to Assess the Quality and Stability of Fruit Products: An Example Using Red Mombin Pulp (Spondias purpurea L.)

Todisco, Katieli Martins; Castro-Alves, Victor Costa; Garruti, Deborah dos Santos; Correia da Costa, Jose Maria; Clemente, Edmar
Fonte: Mdpi Ag Publicador: Mdpi Ag
Tipo: Artigo de Revista Científica Formato: 16851-16860
ENG
Relevância na Pesquisa
46.89%
The present study aimed to evaluate the volatiles profile of red mombin (Spondias purpurea) pulp and its powder produced by spray-drying (SD) as an example to show utility of headspace solid-phase microextraction (HS-SPME) in the analysis of parameters such as the quality and stability of fruit products. Volatiles profiles of the pulp were identified by gas chromatography-mass spectrometry (GC-MS), quantified by gas chromatography-flame ionization detector (GC-FID) and compared to the profile of the powder stored at 0, 60 and 120 days in plastic (PP) or laminated packages (LP). The results showed that the technique was able to identify 36 compounds in the red mombin pulp, 17 out of which have been described for the first time in this fruit, showing that red mombin fresh pulp appears to be unique in terms of volatiles composition. However, only 24 compounds were detected in the powder. This decrease is highly correlated (r(2) = 0.99), at least for the majority of compounds, to the degree of volatility of compounds. Furthermore, the powder stored in PP or LP showed no statistical differences in the amounts of its components for a period of 120 days of storage. Finally, this work shows how HS-SPME analysis can be a valuable tool to assess the quality and stability of fruit products.

Tipificação de meis brasileiros por micro-extração em fase solida combinada com cromatografia gasosa (SPME-CG); Characterization of Brazilian honeys by solid phase microextraction gas chomatography (SPME-CG)

Ana Claudia Lemes da Silva
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 18/12/2006 PT
Relevância na Pesquisa
47.02%
O mel é uma das misturas mais complexas de carboidratos produzida pela natureza. É um alimento energético muito importante pelas suas propriedades nutritivas, pelo seu aroma e sabor que dependem fortemente das plantas, flores e condições climáticas presentes na região geográfica onde está localizada a colméia. Não existem metodologias que possibilitem identificação não subjetiva, rápida e confiável da origem floral do mel. O objetivo deste trabalho foi desenvolver uma metodologia que permitisse a identificação da origem floral de méis brasileiros a partir da caracterização química de sua fração de voláteis utilizando micro-extração em fase sólida através do headspace e cromatografia gasosa (HS-SPME-CG). Para o desenvolvimento da metodologia, foram avaliadas 90 amostras de méis brasileiros de vinte origens florais diferentes e variadas procedências geográficas. Onze destas amostras eram unitárias e permitiram apenas um estudo exploratório. Cada tipo de mel apresentou um perfil cromatográfico diferente. Foram identificados potenciais marcadores para os méis de eucalipto (Eucalyptus sp), laranja (Citrus sp), assa-peixe (Vernonia polianthes), cambará (Lantana montevidensis), morrão de candeia (Croton sp) e marmeleiro (Cydonia vulgaris). Os resultados obtidos mostraram que SPME-CG é útil na tipificação de méis e pode eventualmente ser utilizada na sua certificação; Honey is one of the most complex mixtures of carbohydrates produced by Nature. It is a very important energetic food for its nutritional properties and for its aroma and flavor that depend strongly on the fauna...

Headspace - SPME as a screening system for yeast metabolic compounds : a case study

Martins, Margarida; Henriques, Mariana; Azeredo, Joana; Oliveira, Rosário
Fonte: Universidade do Minho. Departamento de Engenharia Biológica Publicador: Universidade do Minho. Departamento de Engenharia Biológica
Tipo: Conferência ou Objeto de Conferência
Publicado em /09/2008 ENG
Relevância na Pesquisa
56.97%
Aim: This study aimed to identify and quantify the fusel alcohols secreted by the opportunistic yeasts Candida albicans and Candida dubliniensis to further get insights into the amino acid catabolism of those two organisms. Methods and Results: Fusel alcohols were screened in cell - free supernatants of yeasts cultivated in RPMI medium. For simultaneous identification and quantification of these alcohols, a Headspace - Solid Phase Micro Extraction (HS - SPME) coupled with gas chromatography - mass spectrometry (GC - MS) methodology, previously developed to analyse the volatile composition of fruits, was followed (Coelho et al. 2006). Results obtained show that both C. albicans and C. dubliniensis produced isoamyl alcohol and 2- phenylethanol, end – products of the catabolism of the amino acids leucine and phenylalanine, respectively. Significance and Impact of the study: The HS – SPME used herein allows the simultaneous identification and quantification of compounds, requires small sample volume, has high sensitivity and reproducibility, is simple and rapid and is solvent free. This revealed to be a powerful tool for the screening system of yeast metabolic compounds.

Simple and solvent-free methodology for simultaneous quantification of methanol and acetic acid content of plant polysaccharides based on headspace solid phase microextraction-gas chromatography (HS-SPME-GC-FID)

Nunes, Cláudia; Rocha, Sílvia M.; Saraiva, Jorge; Coimbra, Manuel A.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.89%
A simple and solvent-free methodology is proposed for the simultaneous determination of methanol and acetic acid content of any type of plant cell wall polysaccharides. The methanol and acetic acid, released by saponification, are extracted from the headspace of the aqueous solution by solid phase microextraction (HS-SPME) using a DVB/Carboxen/PDMS fibre. The analytes are separated by gas chromatography and detected using a flame ionization detector (GC-FID). The quantification of methanol and acetic acid is done using external calibration curves. A linear relationship between the concentration of methanol (40–100 mg L−1) and acetic acid (25–105 mg L−1) and their GC peak area was observed (r2=0.987 and 0.988, respectively) with a reproducibility of 10%. HS-SPME-GC-FID revealed to be a clean, simple, fast and reliable methodology for the determination of the methanol and acetic acid content of cell wall polysaccharide extracts.

Head Space Solid Phase Micro-Extraction (HS - SPME) of volatile organic compounds produced by Sporidiobolus salmonicolor (CBS 2636)

Valduga,Eunice; Valerio,Alexsandra; Treichel,Helen; Nascimento Filho,Irajá; Fúrigo Júnior,Agenor; Di Luccio,Marco
Fonte: Sociedade Brasileira de Ciência e Tecnologia de Alimentos Publicador: Sociedade Brasileira de Ciência e Tecnologia de Alimentos
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2010 EN
Relevância na Pesquisa
56.79%
The aim of the present study was the assessment of volatile organic compounds produced by Sporidiobolus salmonicolor (CBS 2636) using methyl and ethyl ricinoleate, ricinoleic acid and castor oil as precursors. The analysis of the volatile organic compounds was carried out using Head Space Solid Phase Micro-Extraction (HS - SPME). Factorial experimental design was used for investigating extraction conditions, verifying stirring rate (0-400 rpm), temperature (25-60 ºC), extraction time (10-30 minutes), and sample volume (2-3 mL). The identification of volatile organic compounds was carried out by Gas Chromatography with Mass Spectrum Detector (GC/MSD). The conditions that resulted in maximum extraction were: 60 ºC, 10 minutes extraction, no stirring, sample volume of 2.0 mL, and addition of saturated KCl (1:10 v/v). In the bio-production of volatile organic compounds the effect of stirring rate (120-200 rpm), temperature (23-33 ºC), pH (4.0-8.0), precursor concentration (0.02-0.1%), mannitol (0-6%), and asparagine concentration (0-0.2%) was investigated. The bio-production at 28 ºC, 160 rpm, pH 6,0 and with the addition of 0.02% ricinoleic acid to the medium yielded the highest production of VOCs, identified as 1,4-butanediol, 1...

(E)-2-Nonenal determination in brazilian beers using headspace solid-phase microextraction and gas chromatographic coupled mass spectrometry (HS-SPME-GC-MS)

Scherer,Rodrigo; Wagner,Roger; Kowalski,Cláudia Hoffmann; Godoy,Helena Teixeira
Fonte: Sociedade Brasileira de Ciência e Tecnologia de Alimentos Publicador: Sociedade Brasileira de Ciência e Tecnologia de Alimentos
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2010 EN
Relevância na Pesquisa
56.79%
(E)-2-nonenal is considered an important off-flavor of beer, related to the flavor of beer staling. In this study, a new method for determination of (E)-2-nonenal in beer using headspace solid-phase microextraction and gas chromatographic coupled mass spectrometry (HS-SPME-GC-MS) was developed and applied in Brazilian beer samples. The extractions were carried out in CAR-PDMS (carboxen-polydimethylsiloxane) fiber and the best results were found with 15 minutes of equilibrium and 90 minutes of extraction at 50 °C. The method was linear in the range from 0.02 to 4.0 μg.L-1 with correlation coefficient of 0.9994. The limits of detection and quantification were 0.01 and 0.02 μg.L-1, respectively. 96.5% of recovery and 4% precision (RSD) were obtained in the fortification of beer samples with 2.0 μg.L-1 of (E)-2-nonenal. The developed method proved to be simple, efficient and highly sensitive to the determination of this analyte being easily applied in the quality control of the brewery. (E)-2-nonenal was found in all beer samples analyzed with levels between 0.17 and 0.42 μg.L-1.

A Headspace Solid Phase Microextraction (HS-SPME) method for the chromatographic determination of alkylpyrazines in cocoa samples

Pini,Gláucia F.; Brito,Edy S. de; García,Nelson H.P.; Valente,Antonio L. P.; Augusto,Fabio
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2004 EN
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57.03%
A Headspace Solid Phase Microextraction (HS-SPME) procedure for isolation and determination of alkylpyrazines in cocoa liquor, using Gas Chromatography with Flame Ionization Detection (GC-FID) for the separation and detection of the analytes, is presented here. The HS-SPME operational conditions were optimized using extractions of samples spiked with known amounts of alkylpyrazines typically found on cocoa products. The maximum extraction efficiency was obtained using SPME fibers coated with 65 µm Carbowax/divinylbenzene. Additionally, the best results were achieved with extraction temperature of 60 ºC, 15 min of sample/headspace equilibration time and 45 min extraction time. It was also observed that suspending the samples in saturated aqueous NaCl solution during extractions resulted in a significant increment on the peak areas. This procedure was found to be effective to determine the so-called pyrazinic ratios (quotient between peak areas of alkylpyrazines), which are useful as quality parameters for cocoa liquor.

Isolation and quantification of dialkylmercury species by headspace solid phase microextraction and gas Chromatography with Atomic Emission detection

Oliveira,Ana M.; Silva,Gilmare A.; Poppi,Ronei J.; Augusto,Fabio
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2008 EN
Relevância na Pesquisa
46.89%
A methodology to quantify dialkylmercury compounds using Headspace Solid Phase Microextraction (HS-SPME) and Gas Chromatography with Atomic Emission Detection (GC-AED) was developed. The parameters for Hg detection were optimized by factorial design and response surfaces. Univariate experiments were employed to determine the HS-SPME conditions; 75 μm Carboxen / PDMS and 65 μm PDMS / DVB were the best fibers. However, the former was excluded from further experiments due to extensive thermal degradation of analytes during desorption. The optimized procedure allowed detection of the analytes from aqueous samples with LOD of 1.7 ng L-1 and 0.2 ng L-1 for dimethyl- and diethylmercury, respectively. The analytical curves are linear in the range from 36 to 180 ng L-1 (Me2Hg) and 38 to 190 ng L-1 (Et2Hg), with LOQ of 38 ng L-1 (Me2Hg) and 29 ng L-1 (Et2Hg) and correlation coefficients of 0.998 for Me2Hg and 0.999 for Et2Hg.

Application of Headspace Solid-Phase Microextraction and Gas Chromatography- Mass Spectrometry (HS-SPME-GC/MS) on the Evaluation of Degradation Efficiency of Phenolic Compounds and Identification of By-Products from Produced Water

Silva,Cesar A.; Madureira,Luiz A. S.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2015 EN
Relevância na Pesquisa
56.79%
Application of the headspace solid-phase microextraction and gas chromatography-mass spectrometry (HS-SPME-GC/MS) technique as an analytical tool to monitoring the degradation of phenolic compounds and the formation of by-products in produced water by UV photolysis and UV/peroxide is proposed. All of the experimental conditions for the degradation tests were carried out according to the response of the surface modeling methods developed. The direct photolysis and the UV/H2O2 processes were capable to degrade more than 99% of the initial concentrations of total phenolic components of produced water. The main by-product found was 2,6-di-tert-butylbenzoquinone (DBQ). The presence of DBQ and other hydroxy compounds, constituting the major fraction of by-products identified, demonstrates that the degradations are initiated by the oxidation of the aromatic phenolic ring generating quinones, diphenols, benzoic acids and phenones.

Volatile profile analysis and quality prediction of Longjing tea (Camellia sinensis) by HS-SPME/GC-MS

Lin, Jie; Dai, Yi; Guo, Ya-nan; Xu, Hai-rong; Wang, Xiao-chang
Fonte: Zhejiang University Press Publicador: Zhejiang University Press
Tipo: Artigo de Revista Científica
Publicado em /12/2012 EN
Relevância na Pesquisa
46.89%
This study aimed to analyze the volatile chemical profile of Longjing tea, and further develop a prediction model for aroma quality of Longjing tea based on potent odorants. A total of 21 Longjing samples were analyzed by headspace solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Pearson’s linear correlation analysis and partial least square (PLS) regression were applied to investigate the relationship between sensory aroma scores and the volatile compounds. Results showed that 60 volatile compounds could be commonly detected in this famous green tea. Terpenes and esters were two major groups characterized, representing 33.89% and 15.53% of the total peak area respectively. Ten compounds were determined to contribute significantly to the perceived aroma quality of Longjing tea, especially linalool (0.701), nonanal (0.738), (Z)-3-hexenyl hexanoate (−0.785), and β-ionone (−0.763). On the basis of these 10 compounds, a model (correlation coefficient of 89.4% and cross-validated correlation coefficient of 80.4%) was constructed to predict the aroma quality of Longjing tea. Summarily, this study has provided a novel option for quality prediction of green tea based on HS-SPME/GC-MS technique.

Development of a Direct Headspace Collection Method from Arabidopsis Seedlings Using HS-SPME-GC-TOF-MS Analysis

Kusano, Miyako; Iizuka, Yumiko; Kobayashi, Makoto; Fukushima, Atsushi; Saito, Kazuki
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Publicado em 09/04/2013 EN
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Plants produce various volatile organic compounds (VOCs), which are thought to be a crucial factor in their interactions with harmful insects, plants and animals. Composition of VOCs may differ when plants are grown under different nutrient conditions, i.e., macronutrient-deficient conditions. However, in plants, relationships between macronutrient assimilation and VOC composition remain unclear. In order to identify the kinds of VOCs that can be emitted when plants are grown under various environmental conditions, we established a conventional method for VOC profiling in Arabidopsis thaliana (Arabidopsis) involving headspace-solid-phase microextraction-gas chromatography-time-of-flight-mass spectrometry (HS-SPME-GC-TOF-MS). We grew Arabidopsis seedlings in an HS vial to directly perform HS analysis. To maximize the analytical performance of VOCs, we optimized the extraction method and the analytical conditions of HP-SPME-GC-TOF-MS. Using the optimized method, we conducted VOC profiling of Arabidopsis seedlings, which were grown under two different nutrition conditions, nutrition-rich and nutrition-deficient conditions. The VOC profiles clearly showed a distinct pattern with respect to each condition. This study suggests that HS-SPME-GC-TOF-MS analysis has immense potential to detect changes in the levels of VOCs in not only Arabidopsis...

HS-SPME-GC-MS ANALYSIS OF VOLATILE AND SEMI-VOLATILE COMPOUNDS FROM DRIED LEAVES OF Mikania glomerata Sprengel

Cappelaro,Esmeraldo A.; Yariwake,Janete H.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2015 EN
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This paper reports on the identification of volatile and semi-volatile compounds and a comparison of the chromatographic profiles obtained by Headspace Solid-Phase Microextraction/Gas Chromatography with Mass Spectrometry detection (HS-SPME-GC-MS) of dried leaves of Mikania glomerata Sprengel (Asteraceae), also known as 'guaco.' Three different types of commercial SPME fibers were tested: polydimethylsiloxane (PDMS), polydimethylsiloxane/divinylbenzene (PDMS/DVB) and polyacrylate (PA). Fifty-nine compounds were fully identified by HS-SPME-HRGC-MS, including coumarin, a marker for the quality control of guaco-based phytomedicines; most of the other identified compounds were mono- and sesquiterpenes. PA fibers performed better in the analysis of coumarin, while PDMS-DVB proved to be the best choice for a general and non-selective analysis of volatile and semi-volatile guaco-based compounds. The SPME method is faster and requires a smaller sample than conventional hydrodistillation of essential oils, providing a general overview of the volatile and semi-volatile compounds of M. glomerata.

Volatile profiles of sparkling wines obtained by three extraction methods and gas chromatography–mass spectrometry (GC–MS) analysis

Bosch-Fusté, Joan; Riu-Aumatell, Montserrat; Guadayol, Josep M.; Caixach Gamisans, Josep; López-Tamames, Elvira; Buxaderas, Susana
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 19968 bytes; application/msword
ENG
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8 pages, 1 figure.; Simultaneous distillation extraction (SDE) and closed-loop stripping analysis (CLSA) show great capacity for organic compound extraction. Here we used these techniques to obtain and characterize a wide range of volatile compounds from aged cava sparkling wine. We also explored the potential application of head space-solid phase micro extraction (HS-SPME) to determine the distinctive volatile compounds of aged cava as this technique is a common extraction method in quality flavour control. For SDE, 50 mL of cava were extracted with pentane/dichloromethane during 4 h in a Likens–Nickerson (LN) extraction apparatus; while for CLSA, 25 mL of cava were stirred during 1 h into a CLSA apparatus with an adsorbent trap of granulated activated carbon. HS-SPME was performed at 35ºC using 2 ml of sample for 30 min. The 20-mm SPME fibber was coated with a 50/30-lm layer of divinylbenzene–carboxen–polydimethylsiloxane (DVB–CAR–PDMS). All the extraction methods were followed by gas chromatography–mass spectrometry (GC–MS) analysis. SDE and CLSA allowed the identification of 84 volatile compounds. Almost 40% of the volatiles from these two techniques were obtained by HS-SPME. Moreover, here we provide the first description of several tentatively identified compounds such as lilial...