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Determination of eight fatty acid ethyl esters in meconium samples by headspace solid-phase microextraction and gas chromatography-mass spectrometry

ROEHSIG, Marli; PAULA, Daniela Mendes Louzada de; MOURA, Sidnei; DINIZ, Edna Maria de Albuquerque; YONAMINE, Mauricio
Fonte: WILEY-V C H VERLAG GMBH Publicador: WILEY-V C H VERLAG GMBH
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
116.46%
A number of fatty acid ethyl esters (FAEEs) have recently been detected in meconium samples. Several of these FAEEs have been evaluated as possible biomarkers for in utero ethanol exposure. In the present study, a method was optimized and validated for the simultaneous determination of eight FAEEs (ethyl laurate, ethyl myristate, ethyl palmitate, ethyl palmitoleate, ethyl stearate, ethyl oleate, ethyl linoleate and ethyl arachidonate) in meconium samples. FAEEs were extracted by headspace solid-phase microextraction. Analyte detection and quantification were carried out using GC-MS operated in chemical ionization mode. The corresponding D5-ethyl esters were synthesized and used as internal standards. The LOQ and LOD for each analyte were <150 and <100 ng/g, respectively. The method showed good linearity (r(2)>0.98) in the concentration range studied (LOQ -2000 ng/g). The intra- and interday imprecision, given by the RSD of the method, was lower than 15% for all FAEEs studied. The validated method was applied to 63 authentic specimens. FAEEs could be detected in alcohol-exposed newborns ( >600 ng/g cumulative concentration). Interestingly, FAEEs could also be detected in some non-exposed newborns, although the concentrations were much lower than those measured in exposed cases.; Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[2007/00465-2]; Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[2007/01420-2]

Determination of volatile organic compounds in recycled polyethylene terephthalate and high-density polyethylene by headspace solid phase microextraction gas chromatography mass spectrometry to evaluate the efficiency of recycling processes

DUTRA, Camila; PEZO, Davinson; FREIRE, Maria Teresa de Alvarenga; NERIN, Cristina; REYES, Felix Guillermo Reyes
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
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A method for the determination of volatile organic compounds (VOCs) in recycled polyethylene terephthalate and high-density polyethylene using headspace sampling by solid-phase microextraction and gas chromatography coupled to mass spectrometry detection is presented. This method was used to evaluate the efficiency of cleaning processes for VOC removal from recycled PET. In addition, the method was also employed to evaluate the level of VOC contamination in multilayer packaging material containing recycled HDPE material. The optimisation of the extraction procedure for volatile compounds was performed and the best extraction conditions were found using a 75 mu m carboxen-polydimethylsiloxane (CAR-PDMS) fibre for 20 min at 60 degrees C. The validation parameters for the established method were linear range, linearity, sensitivity, precision (repeatability), accuracy (recovery) and detection and quantification limits. The results indicated that the method could easily be used in quality control for the production of recycled PET and HDPE. (C) 2011 Elsevier B.V. All rights reserved.; CAPES; CNPq, Brazil; Gobierno de Aragon, through the GUIA group of Grupo Consolidado de Investigacion T-10-Universidad de Zaragoza

Determinação de canabinóides em cabelo por microextração em fase sólida por Headspace e análise por espectrometria de massa associada à cromatografia em fase gasosa; Determination of cannabinoids in hair by Headspace solid-phase microextraction and gas chromatography-mass spectrometry

Oliveira, Carolina Dizioli Rodrigues de
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 21/07/2005 PT
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Foi desenvolvido um método para determinar canabinóides (canabidiol, canabinol e delta-9-tetraidrocanabinol) no cabelo. Uma amostra de 10mg foi descontaminada com diclorometano, seguida de digestão alcalina, microextração em fase sólida por headspace (HS-SPME) e analisada por espectrometria de massa associada à cromatografia em fase gasosa (GC/MS). Os limites de detecção e de quantificação foram de 0,07 e 0,12 ng/mg, respectivamente, para todos canabinóides estudados. O método demonstrou ser simples, rápido, preciso e linear no intervalo de 0,12 a 12 ng/mg (r2 > 0,98). Amostras de cabelo de 8 usuários de Cannabis foram coletadas de pacientes provenientes de uma clínica dependentes pela equipe médica. O método mostrou-se eficiente em amostras de cabelos de usuários que faziam uso da droga pelo menos 10 vezes por semana.; A method was to develop to detect cannabinoids (cannabidiol, cannabinol and delta-9-tetrahydrocannabinol) in hair. A 10 mg of hair sample was descontaminated by dichloromethane followed by alkalin digestion, headspace solid-phase microextraction technique (HS-SPME) and analyzed by gas chromatography-mass spectrometry (CG/MS). The detection and quantitation limits were 0,07 and 0,12ng/mg respectively for all studied cannabinoids. The method proved to be simple...

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
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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.

Extração de especies organoestancias em sedimento por microextração em fase solida acoplada ao forno de grafite e determinação de estanho total por amostragem em suspensão; Extraction of organotin species in sediment employing solid phase microextraction coupled to graphite furnace and total tin determination by slurry sampling

Aline Soriano Lopes
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 14/08/2009 PT
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Este trabalho de Tese visa acoplar a fibra, empregada em microextração em fase sólida (SPME, do inglês solid phase microextraction), ao espectrômetro de absorção atômica com forno de grafite (GF AAS, do inglês graphite furnace atomic absorption spectrometer), visando reter espécies organometálicas volatilizadas nas etapas de secagem e pirólise do GF AAS. O elemento escolhido para avaliar o acoplamento SPME-GF AAS foi o Sn. Primeiramente, a concentração total de Sn foi determinada, utilizando a amostragem em suspensão como estratégia, uma vez que na avaliação da distribuição dos compostos organoestânicos por SPME-GF AAS, a concentração total de Sn seria efetuada a partir de uma suspensão. Para a otimização do método foram avaliados os seguintes parâmetros: solução de preparo da suspensão, e efeito da temperatura de pirólise e atomização. A mistura contendo HF 10 % (v/v) e HNO3 1 % (v/v) foi escolhida para preparar a suspensão, a composição Mg(NO3)2 + NH4H2PO4 apresentou resultados apropriados para ser utilizada como modificador químico convencional, e 1000 e 2200 °C foram as temperaturas ótimas para a pirólise e a atomização, respectivamente. Devido ao efeito de matriz, foi utilizada a técnica de adição de analito para a quantificação de Sn em suspensões de sedimento marinho e de rio...

Novas abordagens para microextração em fase sólida (SPME) : extração empregando fibra resfriada e uso de recobrimentos poliméricos iônicos líquidos; New approaches to solid-phase microextraction (SPME) : cold fiber extractions and polimeric ionic liquid sorbent coatings

Bruna Regina de Toledo Sampaio
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 06/03/2015 PT
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Nesta dissertação é descrita duas novas abordagens para microextração em fase sólida. A primeira delas tem como objetivo aumentar a massa extraída já que a mesma é limitada pelo reduzido volume da fase extratora. Para isso, foi proposto o desenvolvimento de um dispositivo, no qual ocorre a compartimentalização do processo de dessorção dos analitos da matriz e a sorção dos mesmos pela fibra de SPME. Dessa forma é possível operar simultaneamente nas temperaturas ótimas de cada processo. O processo de extração ocorre no modo headspace dinâmico, no qual um gás de purga é percolado pela matriz, tornando-se saturado pelos analitos. Este gás transporta os analitos para o interior do dispositivo onde os mesmos serão extraídos pela fibra de SPME resfriada. Esse resfriamento é necessário pois a sorção do analitos pela fibra é um processo exotérmico. Já a segunda abordagem propõe a confecção de novas fibras sortivas baseadas em polímeros iônicos líquidos com o intuito de expandir a aplicabilidade da SPME pois comercialmente, a quantidade de fibras disponíveis é bastante limitada, principalmente no que se refere à extração de analitos polares. Nesta abordagem foi possível a criação de uma nova rota para confecção de fibras baseadas em polímeros iônicos líquidos empregando-se nitinol como suporte...

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
106.52%
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.

Determination of polychlorinated biphenyls in seawater using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry with the aid of experimental design

Song,Xingliang; Li,Jinhua; Chen,Lingxin; Cai,Zongwei; Liao,Chunyang; Peng,Hailong; Xiong,Hua
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 EN
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A simple and reliable pretreatment approach in gas chromatography-mass spectrometry (GC-MS) was developed for concurrent clean-up of seawater and the concentration of lipophilic polychlorinated biphenyls (PCBs) with 1-8 chlorine atoms based on the combination of KMnO4 oxidation with headspace sampling and solid-phase microextraction (SPME). Factors affecting the extraction process were studied using a multivariable approach. Under optimum conditions such as PDMS 7 µm of fiber, 78 ºC of extraction temperature, 33 min of extraction time, 8 mL of volume, the limits of detection ranged from 0.3 to 7.5 ng L-1 and precisions were between 3.9 and 9.9% at spiked 0.05 µg L-1 PCBs. Humic acids in seawater exhibited remarkably negative effects; recoveries of PCBs were significantly improved, especially for more lipophilic CB171 and CB201 from 35% and 49% to 78% and 89%, respectively, after KMnO4 pretreating seawater samples at pH 6. The developed method was demonstrated to be simple, rapid, reliable and applicable for determining different PCBs in seawater containing large amounts of humic substances.

Comparative study of the whisky aroma profile based on headspace solid phase microextraction using different fibre coatings

Câmara, J. S.; Marques, J. C.; Perestrelo, R. M.; Rodrigues, F.; Oliveira, L.; Andrade, P.; Caldeira, M.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /05/2007 ENG
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A dynamic headspace solid-phase microextraction (HS-SPME) and gas chromatography coupled to ion trap mass spectrometry (GC–ITMS) method was developed and applied for the qualitative determination of the volatile compounds present in commercial whisky samples which alcoholic content was previously adjusted to 13% (v/v). Headspace SPME experimental conditions, such as fibre coating, extraction temperature and extraction time, were optimized in order to improve the extraction process. Five different SPME fibres were used in this study, namely, poly(dimethylsiloxane)(PDMS),poly(acrylate)(PA),Carboxen-poly(dimethylsiloxane)(CAR/PDMS),Carbowax-divinylbenzene(CW/DVB)and Carboxen-poly(dimethylsiloxane)-divinylbenzene (CAR/PDMS/DVB). The best results were obtained using a 75 m CAR/PDMS fibre during headspace extraction at 40◦C with stirring at 750rpm for 60min, after saturating the samples with salt. The optimised methodology was then appliedtoinvestigatethevolatilecompositionprofileofthreeScotchwhiskysamples—BlackLabel,BallantinesandHighlandClan.Approximately seventy volatile compounds were identified in the these samples, pertaining at several chemical groups, mainly fatty acids ethyl esters, higher alcohols, fatty acids, carbonyl compounds...

Screening of volatile composition from portuguese multifloral honeys using headspace solid-phase microextraction-gas chromatography–quadrupole mass spectrometry

Pontes, M.; Marques, J. C.; Câmara, J. S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /11/2007 ENG
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The volatile composition from four types of multifloral Portuguese (produced in Madeira Island) honeys was investigated by a suitable analytical procedure based on dynamic headspace solid-phase microextraction (HS-SPME) followed by thermal desorption gas chromatography–quadrupole mass spectrometry detection (GC–qMS). The performance of five commercially available SPME fibres: 100 μm polydimethylsiloxane, PDMS; 85 μm polyacrylate, PA; 50/30 μm divinylbenzene/carboxen on polydimethylsiloxane, DVB/CAR/PDMS (StableFlex); 75 μm carboxen/polydimethylsiloxane, CAR/PDMS, and 65 μm carbowax/divinylbenzene, CW/DVB; were evaluated and compared. The highest amounts of extract, in terms of the maximum signal obtained for the total volatile composition, were obtained with a DVB/CAR/PDMS coating fibre at 60 °C during an extraction time of 40 min with a constant stirring at 750 rpm, after saturating the sample with NaCl (30%). Using this methodology more than one hundred volatile compounds, belonging to different biosynthetic pathways were identified, including monoterpenols, C13-norisoprenoids, sesquiterpenes, higher alcohols, ethyl esters and fatty acids. The main components of the HS-SPME samples of honey were in average ethanol, hotrienol...

Comparative analysis of the volatile fraction from Annona cherimola Mill. cultivars by solid-phase microextraction and gas chromatography–quadrupole mass spectrometry detection

Ferreira, Liseth; Perestrelo, Rosa; Câmara, J. S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /01/2009 ENG
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The analysis of volatile compounds in Funchal, Madeira, Mateus and Perry Vidal cultivars of Annona cherimola Mill. (cherimoya) was carried out by headspace solid-phase microextraction (HS-SPME) combined with gas chromatography–quadrupole mass spectrometry detection (GC–qMSD). HS-SPME technique was optimized in terms of fibre selection, extraction time, extraction temperature and sample amount to reach the best extraction efficiency. The best result was obtained with 2 g of sample, using a divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fibre for 30 min at 30 °C under constant magnetic stirring (800 rpm). After optimization of the extraction methodology, all the cherimoya samples were analysed with the best conditions that allowed to identify about 60 volatile compounds. The major compounds identified in the four cherimoya cultivars were methyl butanoate, butyl butanoate, 3-methylbutyl butanoate, 3-methylbutyl 3-methylbutanoate and 5-hydroxymethyl-2-furfural. These compounds represent 69.08 ± 5.22%, 56.56 ± 15.36%, 56.69 ± 9.28% and 71.82 ± 1.29% of the total volatiles for Funchal, Madeira, Mateus and Perry Vidal cultivars, respectively. This study showed that each cherimoya cultivars have 40 common compounds...

Development of a dynamic headspace solid-phase microextraction procedure coupled to GC–qMSD for evaluation the chemical profile in alcoholic beverages

Rodrigues, F.; Caldeira, M.; Câmara, J. S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /02/2008 ENG
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In the present study, a simple and sensitive methodology based on dynamic headspace solid-phase microextraction (HS-SPME) followed by thermal desorption gas chromatography with quadrupole mass detection (GC–qMSD), was developed and optimized for the determination of volatile (VOCs) and semi-volatile (SVOCs) compounds from different alcoholic beverages: wine, beer and whisky. Key experimental factors influencing the equilibrium of the VOCs and SVOCs between the sample and the SPME fibre, as the type of fibre coating, extraction time and temperature, sample stirring and ionic strength, were optimized. The performance of five commercially available SPME fibres was evaluated and compared, namely polydimethylsiloxane (PDMS, 100 μm); polyacrylate (PA, 85 μm); polydimethylsiloxane/divinylbenzene (PDMS/DVB, 65 μm); carboxen™/polydimethylsiloxane (CAR/PDMS, 75 μm) and the divinylbenzene/carboxen on polydimethylsiloxane (DVB/CAR/PDMS, 50/30 μm) (StableFlex). An objective comparison among different alcoholic beverages has been established in terms of qualitative and semi-quantitative differences on volatile and semi-volatile compounds. These compounds belong to several chemical families, including higher alcohols, ethyl esters, fatty acids...

Volatile flavour constituent patterns of terras madeirenses red wines extracted by dynamic headspace solid‐phase microextraction

Perestrelo, Rosa; Caldeira, Michael; Rodrigues, Freddy
Fonte: Wilei Publicador: Wilei
Tipo: Artigo de Revista Científica
Publicado em //2008 ENG
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A suitable analytical procedure based on static headspace solid-phase microextraction (SPME) followed by thermal desorption gas chromatography–ion trap mass spectrometry detection (GC–ITDMS), was developed and applied for the qualitative and semi-quantitative analysis of volatile components of Portuguese Terras Madeirenses red wines. The headspace SPME method was optimised in terms of fibre coating, extraction time, and extraction temperature. The performance of three commercially available SPME fibres, viz. 100 lm polydimethylsiloxane; 85 lm polyacrylate, PA; and 50/30 lm divinylbenzene/carboxen on polydimethylsiloxane, was evaluated and compared. The highest amounts extracted, in terms of the maximum signal recorded for the total volatile composition, were obtained with a PA coating fibre at 308C during an extraction time of 60 min with a constant stirring at 750 rpm, after saturation of the sample with NaCl (30%, w/v). More than sixty volatile compounds, belonging to different biosynthetic pathways, have been identified, including fatty acid ethyl esters, higher alcohols, fatty acids, higher alcohol acetates, isoamyl esters, carbonyl compounds, and monoterpenols/C13-norisoprenoids.

Profiling allergic asthma volatile metabolic patterns using a headspace-solid phase microextraction/gas chromatography based methodology

Caldeira, M.; Barros, A. S.; Bilelo, M. J.; Parada, A.; Câmara, J. S.; Rocha, S. M.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /06/2011 ENG
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Allergicasthmarepresentsanimportantpublichealthissuewithsignificantgrowthovertheyears,especially in the paediatric population. Exhaled breath is a non-invasive, easily performed and rapid method forobtainingsamplesfromthelowerrespiratorytract.Inthepresentmanuscript,themetabolicvolatile profiles of allergic asthma and control children were evaluated by headspace solid-phase microextraction combined with gas chromatography–quadrupole mass spectrometry (HS-SPME/GC–qMS). The lack ofstudiesinbreathofallergicasthmaticchildrenbyHS-SPMEledtothedevelopmentofanexperimental design to optimize SPME parameters. To fulfil this objective, three important HS-SPME experimental parameters that influence the extraction efficiency, namely fibre coating, temperature and time extractions were considered. The selected conditions that promoted higher extraction efficiency corresponding to the higher GC peak areas and number of compounds were: DVB/CAR/PDMS coating fibre, 22◦C and 60min as the extraction temperature and time, respectively. The suitability of two containers, 1L Tedlar® bags and BIOVOC®, for breath collection and intra-individual variability were also investigated. The developed methodology was then applied to the analysis of children exhaled breath with allergicasthma(35)...

Dynamic headspace solid-phase microextraction combined with one-dimensional gas chromatography–mass spectrometry as a powerful tool to differentiate banana cultivars based on their volatile metabolite profile

Pontes, Marisela; Pereira, Jorge; Câmara, José S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /04/2012 ENG
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In this study the effect of the cultivar on the volatile profile of five different banana varieties was evaluated and determined by dynamic headspace solid-phase microextraction (dHS-SPME) combined with one-dimensional gas chromatography–mass spectrometry (1D-GC–qMS). This approach allowed the definition of a volatile metabolite profile to each banana variety and can be used as pertinent criteria of differentiation. The investigated banana varieties (Dwarf Cavendish, Prata, Maçã, Ouro and Platano) have certified botanical origin and belong to the Musaceae family, the most common genomic group cultivated in Madeira Island (Portugal). The influence of dHS-SPME experimental factors, namely, fibre coating, extraction time and extraction temperature, on the equilibrium headspace analysis was investigated and optimised using univariate optimisation design. A total of 68 volatile organic metabolites (VOMs) were tentatively identified and used to profile the volatile composition in different banana cultivars, thus emphasising the sensitivity and applicability of SPME for establishment of the volatile metabolomic pattern of plant secondary metabolites. Ethyl esters were found to comprise the largest chemical class accounting 80.9%, 86.5%...

Methylmercury determination in biota by solid-phase microextraction matrix effect evaluation

Carrasco Cabrera, Luis; Díez Salvador, Sergi; Bayona Termens, Josep María
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 19968 bytes; application/msword
ENG
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5 pages, 4 figures.-- PMID: 17936289 [PubMed].-- Printed version published on Dec 7, 2007.; Issue title: ExTech 2007 - 9th International Symposium on Advances in Extraction Technologies (Alesund, Norway, June 3-6, 2007).; Aqueous-phase alkylation followed by, headspace solid-phase microextraction (SPME) for mercury speciation in biota, was developed a decade ago. Despite this, matrix effects in this technique have not yet been addressed. In this paper, the importance of these effects has been assessed and overcome by standard addition calibration. Furthermore, improvements were made in the extraction of methylmercury (MeHg) from biological matrixes by optimizing the matrix digestion procedure (temperature and digestion time) and the SPME parameters (aliquot volume of digested samples, extraction temperature and fibre coating), which aimed to minimize the matrix effects. Accordingly, samples were alkaline digested (KOH, 25%, w/v, 60ºC, 180 min) and an aliquot was propylated using an aqueous NaBPr4 solution, headspace SPME sampling and, finally, by using GC-pyrolysis (Py)-atomic fluorescence spectrometry (AFS) determination. The procedure developed was validated using dogfish muscle reference material NRCC DORM-2.; Financial support was obtained from the Spanish Ministry of Environment and the ACA (Generalitat de Catalunya). Authors acknowledge the collaboration of J. Benito...

Solid phase microextraction as a reliable alternative to conventional extraction techniques to evaluate the pattern of hydrolytically released components in Vitis vinifera L. grapes

Perestrelo, Rosa; Caldeira, Michael; Câmara, José S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /06/2012 ENG
Relevância na Pesquisa
106.33%
In present research, headspace solid-phase microextraction (HS-SPME) followed by gas chromatography–mass spectrometry (GC–qMS), was evaluated as a reliable and improved alternative to the commonly used liquid–liquid extraction (LLE) technique for the establishment of the pattern of hydrolytically released components of 7 Vitis vinifera L. grape varieties, commonly used to produce the world-famous Madeira wine. Since there is no data available on their glycosidic fractions, at a first step, two hydrolyse procedures, acid and enzymatic, were carried out using Boal grapes as matrix. Several parameters susceptible of influencing the hydrolytic process were studied. The best results, expressed as GC peak area, number of identified components and reproducibility, were obtained using ProZym M with b-glucosidase activity at 35 °C for 42 h. For the extraction of hydrolytically released components, HS-SPME technique was evaluated as a reliable and improved alternative to the conventional extraction technique, LLE (ethyl acetate). HS-SPME using DVB/CAR/PDMS as coating fiber displayed an extraction capacity two fold higher than LLE (ethyl acetate). The hydrolyzed fraction was mainly characterized by the occurrence of aliphatic and aromatic alcohols...

Characterization of volatile substances in apples from rosaceae family by headspace solid‐phase microextraction followed by GC‐qMS

Ferreira, Liseth; Perestrelo, Rosa; Caldeira, Michael; Câmara, José S.
Fonte: WILEY-VCH Verlag GmbH & Co. KGaA Publicador: WILEY-VCH Verlag GmbH & Co. KGaA
Tipo: Artigo de Revista Científica
Publicado em /03/2009 ENG
Relevância na Pesquisa
116.46%
The volatile composition of different apple varieties of Malus domestica Borkh. species from different geographic regions at Madeira Islands, namely Ponta do Pargo (PP), Porto Santo (PS), and Santo da Serra (SS) was established by headspace solid-phase microextraction (HS-SPME) procedure followed by GC-MS (GC-qMS) analysis. Significant parameters affecting sorption process such as fiber coating, extraction temperature,extractiontime,sampleamount,dilutionfactor,ionicstrength,anddesorption time,wereoptimizedanddiscussed.TheSPMEfibercoatedwith50/30 lmdivinylbenzene/carboxen/PDMS (DVB/CAR/PDMS) afforded highest extraction efficiency of volatile compounds, providing the best sensitivity for the target volatiles, particularly whenthesampleswereextractedat508Cfor30 minwithconstantmagneticstirring. A qualitative and semi-quantitative analysis between the investigated apple species has been established. It was possible to identify about 100 of volatile compounds amongpulp(46,45,and39),peel(64,60,and64),andentirefruit(65,43,and50)inPP, PS,andSSapples,respectively.Ethylesters,terpenes,andhigheralcoholswerefound tobethemostrepresentativevolatiles. a-Farnesene,hexan-1-olandhexyl2-methylbutyratewerethecompoundsfoundinthevolatileprofileofstudiedappleswiththelargestGCarea...

Headspace solid-phase microextraction-gas chromatography-quadrupole mass spectrometric methodology for the establishment of the volatile composition of Passiflora fruit species

Pontes, M.; Marques, J. C.; Câmara, J. S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /09/2009 ENG
Relevância na Pesquisa
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Dynamic headspace solid-phase microextraction (HS-SPME) followed by thermal desorption gas chromatography-quadrupole mass spectrometry analysis (GC-qMS), was used to investigate the aroma profile of different species of passion fruit samples. The performance of five commercially available SPME fibres: 65 μm polydimethylsiloxane/divinylbenzene, PDMS/DVB; 100 μm polydimethylsiloxane, PDMS; 85 μm polyacrylate, PA; 50/30 μm divinylbenzene/carboxen on polydimethylsiloxane, DVB/CAR/PDMS (StableFlex); and 75 μm carboxen/polydimethylsiloxane, CAR/PDMS; was evaluated and compared. Several extraction times and temperature conditions were also tested to achieve optimum recovery. The SPME fibre coated with 65 μm PDMS/DVB afforded the highest extraction efficiency, when the samples were extracted at 50 °C for 40 min with a constant stirring velocity of 750 rpm, after saturating the sample with NaCl (17%, w/v — 0.2 g). A comparison among different passion fruit species has been established in terms of qualitative and semi-quantitative differences in volatile composition. By using the optimal extraction conditions and GC-qMS it was possible to tentatively identify seventy one different compounds in Passiflora species: 51 volatiles in Passiflora edulis Sims (purple passion fruit)...

Potentialities of two solventless extraction approaches—Stir bar sorptive extraction and headspace solid-phase microextraction for determination of higher alcohol acetates, isoamyl esters and ethyl esters in wines

Perestrelo, R.; Nogueira, J. M. F.; Câmara, J. S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /12/2009 ENG
Relevância na Pesquisa
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A stir bar sorptive extraction with liquid desorption followed by large volume injection coupled to gas chromatography–quadrupole mass spectrometry (SBSE-LD/LVI-GC–qMS) was evaluated for the simultaneous determination of higher alcohol acetates (HAA), isoamyl esters (IsoE) and ethyl esters (EE) of fatty acids. The method performance was assessed and compared with other solventless technique, the solid-phase microextraction (SPME) in headspace mode (HS). For both techniques, influential experimental parameters were optimised to provide sensitive and robust methods. The SBSE-LD/LVI methodology was previously optimised in terms of extraction time, influence of ethanol in the matrix, liquid desorption (LD) conditions and instrumental settings. Higher extraction efficiency was obtained using 60 min of extraction time, 10% ethanol content, n-pentane as desorption solvent, 15 min for the back-extraction period, 10 mL min−1 for the solvent vent flow rate and 10 °C for the inlet temperature. For HS-SPME, the fibre coated with 50/30 μm divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) afforded highest extraction efficiency, providing the best sensitivity for the target volatiles, particularly when the samples were extracted at 25 °C for 60 min under continuous stirring in the presence of sodium chloride (10% (w/v)). Both methodologies showed good linearity over the concentration range tested...