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Design, construction and evaluation of a simple pressurized solvent extraction system

PINTO, J. S. S.; LANÇAS, F. M.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.48%
This work describes the construction and testing of a simple pressurized solvent extraction (PSE) system. A mixture of acetone:water (80:20), 80 ºC and 103.5 bar, was used to extract two herbicides (Diuron and Bromacil) from a sample of polluted soil, followed by identification and quantification by high-performance liquid chromatography coupled with diode array detector (HPLC-DAD). The system was also used to extract soybean oil (70 ºC and 69 bar) using pentane. The extracted oil was weighed and characterized through the fatty acid methyl ester analysis (myristic (< 0.3%), palmitic (16.3%), stearic (2.8%), oleic (24.5%), linoleic (46.3%), linolenic (9.6%), araquidic (0.3%), gadoleic (< 0.3%), and behenic (0.3%) acids) using high-resolution gas chromatography with flame ionization detection (HRGC-FID). PSE results were compared with those obtained using classical procedures: Soxhlet extraction for the soybean oil and solid-liquid extraction followed by solid-phase extraction (SLE-SPE) for the herbicides. The results showed: 21.25 ± 0.36% (m/m) of oil in the soybeans using the PSE system and 21.55 ± 0.65% (m/m) using the soxhlet extraction system; extraction efficiency (recovery) of herbicides Diuron and Bromacil of 88.7 ± 4.5% and 106.6 ± 8.1%...

Extração de antocianinas de resíduo de jabuticaba (Myrciaria cauliflora) utilizando líquido pressurizado e fluido supercrítico : caracterização química, avaliação econômica e modelagem matemática; Extraction of anthocyanins from jabuticaba (Myrciaria cauliflora) byproduct using pressurized liquid and supercritical fluid : chemical characterization, economic evaluation and mathematical modeling

Rodrigo Nunes Cavalcanti
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 08/04/2013 PT
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86.55%
Atualmente, o conhecimento científico sobre a utilização de produtos naturais com propriedades funcionais, a exigência do consumidor quanto à qualidade dos alimentos, bem como ações legislativas para redução do uso de corantes sintetizados quimicamente têm propiciado o aumento da utilização de corantes naturais. Dentre estes, as antocianinas constituem pigmentos aquosolúveis responsáveis pelas principais cores encontradas na natureza, podendo variar desde o laranja, vermelho, violeta até o azul. Antocianinas são moléculas polares derivadas do cátion flavilion (C6-C3-C6) constituindo um importante subgrupo dos flavonóides. As principais propriedades biológicas atribuídas às antocianinas são atividade: antiinflamatória, anticarcinogênica e antioxidante. Diversos métodos de extração têm sido utilizados na obtenção de antocianinas. A extração supercrítica apresenta vantagens consideráveis sobre os métodos convencionais: o solvente é facilmente removido do soluto; utiliza pouco ou nenhum solvente orgânico; possibilita uma rápida extração; e, por fim, opera a baixas temperaturas favorecendo a extração de produtos voláteis e termolábeis. Este trabalho visou estudar o processo de extração supercrítica de antocianinas otimizando as diversas etapas do processo através de ensaios experimentais...

Extração de compostos bioativos do bagaço da amora-preta (Rubus spp.) utilizando líquidos pressurizados; Extração de compostos bioativos do bagaço da amora-preta (Rubus spp.) utilizando líquidos pressurizados

Ana Paula da Fonseca Machado
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 28/03/2014 PT
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66.43%
A amora-preta é um fruto rico em compostos fenólicos, com destaque para os pigmentos antociânicos. Além do consumo in natura, a amora-preta é utilizada industrialmente na fabricação de sucos e derivados. Entretanto, este processamento gera cerca de 10 % de resíduos sólidos que contêm ainda uma grande porcentagem de fitoquímicos do fruto. Visando ao aproveitamento desse subproduto, o objetivo desse trabalho foi obter extratos ricos em seus principais compostos bioativos, os polifenóis, empregando a técnica limpa de extração com líquido pressurizado (PLE). Para isso, primeiramente, o bagaço da polpa da amora-preta foi caracterizado quanto ao teor de fenólicos totais (FT), antocianinas monoméricas (AM), atividade antioxidante (AA), pH, sólidos solúveis totais (SS) e composição centesimal. Em seguida, foram realizadas PLE¿s usando 3 temperaturas (60, 80 e 100 ºC) e 4 diferentes solventes (água, água acidificada a pH 2,5, etanol e mistura de etanol e água 50 %), resultando em 12 diferentes ensaios. Nos processos de extração por PLE foram fixados a pressão (75 bar), a razão S/F (18,0), o tempo de corrida (30 min) e a massa de matéria-prima (5,0 g). Posteriormente, foram identificadas as antocianinas majoritárias e minoritárias nos extratos subcríticos por cromatografia líquida de ultra performance (UPLC-QToF-MS). Além da técnica PLE...

Obtenção de extratos enriquecidos em carotenoides e produtos hidrolisados através do fracionamento da fibra de palma prensada com solventes limpos e fluidos pressurizados; Obtaining of carotenoid-rich extracts and hydrolysate products by fractionation of pressed palm fiber using clean solvents and pressurized fluids

Fiorella Patricia Cárdenas Toro
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 26/02/2015 PT
Relevância na Pesquisa
76.5%
A fibra de palma prensada (Elaes guineensis) é um resíduo procedente da indústria de extração de óleo de palma que possui na sua composição compostos bioativos tais como alfa- e beta-caroteno, assim como os polissacarídeos (celulose e hemicelulose). Estes compostos podem ser recuperados mediante processos de extração e hidrólise com a finalidade de produzir de forma sustentável, extratos enriquecidos com carotenoides e produtos hidrolisados com aplicação na indústria química, de alimentos e farmacêutica. Entre as tecnologias que utilizam solventes limpos a altas e baixas pressões, temos a extração por Soxhlet (LPSE-SOX), extração por percolação (LPSE-PE), extração por líquido pressurizado (PLE), extração com fluído supercrítico (SFE) e hidrólise subcrítica com água (SubWH). Neste trabalho, um processo integrado utilizando SFE e SubWH foi proposto como modelo de aproveitamento integral da fibra de palma prensada. O estudo incluiu a avaliação dos efeitos dos parâmetros operacionais de extração: temperatura e pressão empregando uma razão mássica de solvente por massa de matéria-prima (S/F) de 30 na obtenção de um extrato rico em carotenoides; e dos parâmetros operacionais de hidrólise: temperatura...

Design, construction and evaluation of a simple pressurized solvent extraction system

Pinto,J. S. S.; Lanças,F. M.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2009 EN
Relevância na Pesquisa
66.48%
This work describes the construction and testing of a simple pressurized solvent extraction (PSE) system. A mixture of acetone:water (80:20), 80 ºC and 103.5 bar, was used to extract two herbicides (Diuron and Bromacil) from a sample of polluted soil, followed by identification and quantification by high-performance liquid chromatography coupled with diode array detector (HPLC-DAD). The system was also used to extract soybean oil (70 ºC and 69 bar) using pentane. The extracted oil was weighed and characterized through the fatty acid methyl ester analysis (myristic (< 0.3%), palmitic (16.3%), stearic (2.8%), oleic (24.5%), linoleic (46.3%), linolenic (9.6%), araquidic (0.3%), gadoleic (< 0.3%), and behenic (0.3%) acids) using high-resolution gas chromatography with flame ionization detection (HRGC-FID). PSE results were compared with those obtained using classical procedures: Soxhlet extraction for the soybean oil and solid-liquid extraction followed by solid-phase extraction (SLE-SPE) for the herbicides. The results showed: 21.25 ± 0.36% (m/m) of oil in the soybeans using the PSE system and 21.55 ± 0.65% (m/m) using the soxhlet extraction system; extraction efficiency (recovery) of herbicides Diuron and Bromacil of 88.7 ± 4.5% and 106.6 ± 8.1%...

Optimization of Pressurized Liquid Extraction of Three Major Acetophenones from Cynanchum bungei Using a Box-Behnken Design

Li, Wei; Zhao, Li-Chun; Sun, Yin-Shi; Lei, Feng-Jie; Wang, Zi; Gui, Xiong-Bin; Wang, Hui
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 08/11/2012 EN
Relevância na Pesquisa
66.45%
In this work, pressurized liquid extraction (PLE) of three acetophenones (4-hydroxyacetophenone, baishouwubenzophenone, and 2,4-dihydroxyacetophenone) from Cynanchum bungei (ACB) were investigated. The optimal conditions for extraction of ACB were obtained using a Box-Behnken design, consisting of 17 experimental points, as follows: Ethanol (100%) as the extraction solvent at a temperature of 120 °C and an extraction pressure of 1500 psi, using one extraction cycle with a static extraction time of 17 min. The extracted samples were analyzed by high-performance liquid chromatography using an UV detector. Under this optimal condition, the experimental values agreed with the predicted values by analysis of variance. The ACB extraction yield with optimal PLE was higher than that obtained by soxhlet extraction and heat-reflux extraction methods. The results suggest that the PLE method provides a good alternative for acetophenone extraction.

New Strategies for Extraction and Clean-up of Persistent Organic Pollutants from Food and Feed Samples using Selective Pressurized Liquid Extraction

BJOERKLUND Erland; SPORRING Sune; WIBERG Karin; HAGLUND Peter; VON HOLST CHRISTOPH
Fonte: Elsevier Publicador: Elsevier
Tipo: Articles in Journals Formato: Printed
ENG
Relevância na Pesquisa
66.4%
Pressurized liquid extraction (PLE) has gained wide acceptance for the extraction of persistent organic pollutants (POPs) from various environmental and biological matrices. This extraction technique was developed to shorten the extraction step, since this is one of the most time-consuming steps in many analytical procedures. When POPs enter the food chain, as in a number of recent food crises. thousands of samples have to be analyzed in a short time to protect humans from severe POP exposure. In such cases, PLE provides a good alternative to conventional extraction techniques. This article gives an overview of a number of studies of the extraction of POPs from food and feed, using PLE. Of special interest are applications dealing with selective extraction procedures, where integrated clean-up strategies are utilized to combine extraction and clean-up or fractionation to simplify further the entire sample-preparation chain.; JRC.D.8-Food safety and quality

Optimisation of Pressurized Liquid Extraction for the Determination of Seven Selected Polychlorinated Biphenyls in Feed Samples: Effects of High Lipid Amounts and Lipid Type on Fat Retention

VON HOLST CHRISTOPH; MULLER A.; SERANO FEDERICA; SPORRING Sune; BJOERKLUND Erland
Fonte: VIEWEG Publicador: VIEWEG
Tipo: Articles in Journals Formato: Printed
ENG
Relevância na Pesquisa
66.41%
Pressurized liquid extraction was utilized for the extraction of seven selected polychlorinated biphenyls from a naturally contaminated fishmeal and two feed samples fortified with a naturally contaminted fish oil sample. In order to assure sufficient extraction efficiencies, the extraction solvent, the extraction temperature, and the flush volume were optimised by a factorial design approach. The results of the analyses revealed that the impact of these parameters on the extraction of PCBs differed depending on which matrix that was analysed. For fishmeal, an elevated extraction temperature was imprtant to obtain the highest values for the recovery rates whereas for the feed samples high extraction efficiencies could be obtained for all temperatures investigated in the study. In addition, the solvent had an impact on the extraction of PCBs, however, the influence was less pronounced than the impact of temperature. The final conditions, resulting in high recovery rates for all PCBs in matrices, were found to be temperatures above 100°C using n-heptane as extraction solvent, while the flush volume had very limited effects on the extraction efficiency.; JRC.D.8-Food safety and quality

Análise da concentração de compostos bioativos e avaliação da toxicidade aguda in vivo dos diterpenos cafestol e caveol presentes no óleo de grãos de café verdes obtidos por extração supercrítica e por extração com fluido pressurizado; Concentration of bioactive compounds analysis and evaluation of acute toxicity in vivo of the diterpenes cafestol and kahweol from green beans coffee oil obtained by supercritical and pressurized fluid extractions

Oliveira, Naila Albertina 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 22/07/2015 PT
Relevância na Pesquisa
76.59%
Este estudo visou à utilização da tecnologia que emprega CO2 em estado supercrítico (SFE) para estudar a bioatividade dos diterpenos presentes no óleo de café verde, cafestol (C) e caveol (K), contudo propondo também a otimização de extração com líquido pressurizado (PLE) em batelada, utilizando para isto um Delineamento Composto Central Rotacional (DCCR2). O referido tema tem caráter inovador e inédito, já que a tecnologia de extração com líquido pressurizado, até então empregada para extração de analitos, passa a ser estudada em processos de extração de óleos vegetais tais como, óleo de pequi, óleo de café verde, extrato de sementes de pitanga no LTAPPN. Esta técnica utiliza solventes orgânicos e emprega elevada temperatura de extração, o que aumenta a capacidade de solubilização do solvente, e o emprego de altas pressões que acelera a difusão nos poros da matriz já que a viscosidade do solvente é diminuída. Este comportamento ocasiona maior penetração do solvente na matriz, aumentando sua capacidade de extração. A extração supercrítica (SFE) é uma tecnologia limpa, pois não emprega solventes orgânicos sendo promissora na obtenção de extratos enriquecidos com compostos bioativos que possam desempenhar alguma atividade. O estudo da atividade aguda dos diterpenos presentes no óleo de grãos de café verdes obtidos via SFE e PLE demonstrou que o óleo extraído com CO2 supercrítico...

Determination of Benzoxazinone Derivatives in Plants by Combining Chromatography−Electrospray Mass Spectrometry

Villagrasa, Marta; Guillamón, Miriam; Eljarrat, Ethel; Barceló, Damià
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artículo Formato: 19968 bytes; application/msword
ENG
Relevância na Pesquisa
66.41%
8 pages, 6 tables, 4 figures.; A new analytical method based on the use of pressurized liquid extraction (PLE) followed by solid-phase extraction with LiChrolut RP C18 cartridges was evaluated for the sample preparation, extraction, and cleanup of eight naturally occurring benzoxazinone derivatives, 2-β-d-glucopyranosyloxy-4-hydroxy-1,4-benzoxazin-3-one, 2-β-d-glucopyranosyloxy-4-hydroxy-7-methoxy-1,4-benzoxazin-3-one, 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA), 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one, 2-hydroxy-1,4-benzoxazin-3-one, 2-hydroxy-7-methoxy-1,4-benzoxazin-3-one, benzoxazolin-2-one, and 6-methoxybenzoxazolin-2-one in plant samples. Afterward, liquid chromatography−electrospray mass spectrometry, using the selected ion monitoring mode and internal standard (2-MeO-DIBOA, indoxyl-β-d-glucoside, and quercetin-3-O-rutinoside) quantification method was performed. This paper demonstrates the effectiveness of the PLE method, in conjunction with sensitive and specific mass spectrometric detection, for the quantitative recovery of compounds of the benzoxazinone class from plants. The recoveries of the analytes ranged from 66 to 110% with coefficients of variation ranging from 1 to 14%. This method gave detection limits between 1 and 27 μg/g. The method was applied to foliage and roots of three different wheat cultivars...

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
Relevância na Pesquisa
96.6%
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

Pressurized liquid extracts from Spirulina platensis microalga Determination of their antioxidant activity and preliminary analysis by micellar electrokinetic chromatography

Herrero, Miguel; Ibáñez, Elena; Señorans, F. Javier; Cifuentes, Alejandro
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 156452 bytes; application/pdf
ENG
Relevância na Pesquisa
86.46%
In this work, different extracts from the microalga Spirulina platensis are obtained using pressurized liquid extraction (PLE) and four different solvents (hexane, light petroleum, ethanol andwater). Different extraction temperatures (115 and 170 ◦C) were tested using extraction times ranging from 9 to 15 min. The antioxidant activity of the different extracts is determined by means of an in vitro assay using a free radical method. Moreover, a new and fast method is developed using micellar electrokinetic chromatography with diode array detection (MEKC–DAD) to provide a preliminary analysis on the composition of the extracts. This combined application (i.e., in vitro assays plus MEKC–DAD) allowed the fast characterization of the extracts based on their antioxidant activity and the UV–vis spectra of the different compounds found in the extracts. To our knowledge, this work shows for the first time the great possibilities of the combined use of PLE–in vitro assay–MEKC–DAD to investigate natural sources of antioxidants.; MH thanks MCYT for a FPI grant. Authors thank MCYT (project AGL2002-04621-C02-02) for financial support.; Peer reviewed

Pressurized liquid extraction–capillary electrophoresis–mass spectrometry for the analysis of polar antioxidants in rosemary extracts

Herrero, Miguel; Arráez-Román, David; Segura-Carretero, Antonio; Kendler, Ernst; Gius, Beatrice; Raggi, Maria Augusta; Ibáñez, Elena; Cifuentes, Alejandro
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 101401 bytes; application/pdf
ENG
Relevância na Pesquisa
96.46%
A method based on capillary electrophoresis–electrospray–mass spectrometry (CE–ESI–MS) was developed to qualitatively characterize natural antioxidants from rosemary (Rosmarinus officinalis L.) in different fractions obtained by pressurized liquid extraction (PLE) using subcritical water. The parameters of CE–ESI–MS were adjusted allowing the separation and characterization of different compounds from rosemary in the PLE fractions. These parameters for CE are kind, pH and concentration of the separation buffer, parameters for ESI–MS are dry gas temperature and flow, nebulizing gas pressure, and make-up flow. The following analytical conditions were found most favorable: aqueous CE buffer (40mM ammonium acetate/ammonium hydroxide, pH 9); sheath liquid containing 2-propanol–water (60:40, v/v) and 0.1% (v/v) triethylamine at a flow rate of 0.24 mL/h; drying gas flow rate equal to 7 L/min at 350 ◦C, nebulizing gas pressure of 13.8 kPa (2 psi), using a compound stability of 50%. Different antioxidant compounds (e.g., rosmarinic acid and carnosic acid) could be detected in the rosemary extracts by CE–ESI–MS without any additional treatment, enabling the determination of variations in the extract composition caused by the different PLE conditions (i.e....

Capillary electrophoresis-mass spectrometry of Spirulina platensis proteins obtained by pressurized liquid extraction

Herrero, Miguel; Simó, Carolina; Ibáñez, Elena; Cifuentes, Alejandro
Fonte: Wiley-VCH Publicador: Wiley-VCH
Tipo: Artículo Formato: 201723 bytes; application/pdf
ENG
Relevância na Pesquisa
66.51%
In this work, the usefulness of CE-MS to monitor and optimize the pressurized liquid extraction (PLE) of proteins from Spirulina platensis microalga is demonstrated. Crude and purified PLE extracts from microalga were analyzed by CE-MS. It was observed that the use of purification protocols of phycobiliproteins (namely, ultrafiltration or precipitation- dialysis-freeze drying) resulted in better CE resolution and MS signals, demonstrating that sample matrix plays an important role in CE-MS of proteins in real samples. Ultrafiltration was found less laborious and much faster than precipitationdialysis- freeze drying (1 vs. 48 h). Direct analysis of crude extracts was demonstrated to be also possible by CE-MS, providing less-quality information but enough to characterize PLE extracts in a much faster way. Therefore, the latter protocol was selected to monitor and optimize the extraction process of phycobiliproteins from S. platensis. To do that, different extraction conditions were tested, including time, temperature and pressure of extraction, nature of pressurized liquid, distribution of microalga inside the extraction cell, type of packing, etc. It is demonstrated that the combined use of PLE and CE-MS allows the attainment of extracts rich in phycobiliproteins in short extraction times (namely...

Functional characterization of pressurized liquid extracts of Spirulina platensis

Santoyo, Susana; Herrero, Miguel; Señorans, F. Javier; Cifuentes, Alejandro; Ibáñez, Elena; Jaime, Laura
Fonte: Springer Publicador: Springer
Tipo: Artículo Formato: 220221 bytes; application/pdf
ENG
Relevância na Pesquisa
76.44%
Three different parameters (temperature, solvent, and extraction time) were studied regarding to pressure liquid extraction (PLE) of antioxidant and antimicrobial compounds from Spirulina platensis. Two different antioxidant methods, β-carotene bleaching method and DPPH• (2,2-Diphenyl-1-picrylhydrazyl hydrate) free radical scavenging assay, were used to determine the optimal PLE conditions for antioxidants extraction. The selected conditions were as follows: extraction temperature equal to 115 ◦C, extraction time equal to 15 min and ethanol as extracting solvent. The main antioxidant compounds found in this extract were identified as zeaxanthin, a myxoxanthophyll-like compound and very polar phenolic compounds. Moreover, antimicrobial activity of different PLE fractions was tested against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 11775, Candida albicans ATCC 60193, and Aspergillus niger ATCC 16404. Data obtained showed the hexane and petroleum ether extracts were slightly more active than ethanolic extracts. As for water extracts, none of them were active against the microorganisms tested. Data indicated that both 115 and 170 ◦C were the best extraction temperatures conditions in order to optimize the extraction of antimicrobial compounds...

Dunaliella salina microalga pressurized liquid extracts as potential antimicrobials

Herrero, Miguel; Ibáñez, Elena; Cifuentes, Alejandro; Reglero, Guillermo; Santoyo, Susana
Fonte: International Association for Food Protection Publicador: International Association for Food Protection
Tipo: Artículo Formato: 20457 bytes; application/pdf
ENG
Relevância na Pesquisa
76.51%
In the present work, the antimicrobial activity of different pressurized liquid extracts obtained from Dunaliella salina microalga has been tested against several microorganisms of importance for the food industry (Escherichia coli, Staphylococcus aureus, Candida albicans and Aspergillus niger). Different solvents (hexane, petroleum ether, hexane and water) and extraction conditions (40, 100 and 160ºC) have been tested. Results showed that the best antimicrobial activity was obtained, for each solvent, at the highest extraction temperature (160ºC). Likewise, the extraction yield followed the same trend increasing with the extraction temperature and being maximum when ethanol was employed as extraction solvent. Water extracts provided the lowest extraction yields. In general, the best results in terms of antimicrobial activity were obtained using petroleum ether and hexane, although ethanolic extracts presented also good antimicrobial activity. Since the main antimicrobial activity of the extracts was against bacteria, the extracts can be considered to show specifically antibacterial effect. The extracts were analyzed by GC-MS in order to identify the compounds responsible of such activity. 15 different volatile compounds as well as several fatty acids (mainly palmitic...

Determination of decabromodiphenyl ether in sediments using selective pressurized liquid extraction followed by GC-NCI-MS

Eljarrat, Ethel; Cal, Agustina de la; Barceló, Damià
Fonte: Springer Publicador: Springer
Tipo: Artículo Formato: 22195 bytes; application/pdf
ENG
Relevância na Pesquisa
96.43%
5 pages, 3 figures, 2 tables.-- PMID: 14513196 [PubMed].-- Available online Sep 25, 2003.; A method based on selective pressurized liquid extraction (SPLE) followed by gas chromatography–negative ion chemical ionization-mass spectrometry (GC–NCI-MS) has been evaluated for analysis of decabromodiphenyl ether (PBDE-209) in sediment samples. Instrumental operating conditions such as source temperature and system pressure were optimized in the NCI-MS system, giving an instrumental detection limit of 2 pg. The limit of determination of the entire SPLE–GC–NCI-MS procedure was around 50 pg g–1 dry weight (dw), with repeatability of replicates between 4 and 21% relative standard deviation. Application of the method to 13 different river and marine sediment samples collected in Spain revealed that levels of decabromodiphenyl ether ranged between 2 and 132 ng g–1 dry weight.; This work was financially supported by the Ministerio de Ciencia y Tecnología (TRACOAL, PPQ2001–1805-C03–01).; Peer reviewed

Analysis of polycyclic aromatic hydrocarbons in pine needles by gas chromatography–mass spectrometry. Comparison of different extraction and clean-up procedures

Ratola, Nuno; Lacorte Bruguera, Silvia; Alves, Arminda; Barceló, Damià
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 162 bytes; application/msword
ENG
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76.39%
7 pages, 4 figures, 3 tables.-- PMID: 16620846 [PubMed].-- Printed version published May 12, 2006.-- Issue title: ExTech 2005 - 7th International Symposium on Advances in Extraction Technologies (Campinas, Brazil, Nov 13-15, 2005).; Three extraction methodologies (Soxhlet, ultrasonic and pressurized liquid extraction) and several clean-up procedures (Florisil, silica and alumina in cartridges or glass column format) were tested and compared to extract 16 US Environmental Protection Agency (EPA) polycyclic aromatic hydrocarbons (PAHs) from Pinus pinea L. needles. Quantification was done by gas chromatography with mass spectrometry, by internal standard method using five deuterated PAH surrogate standards. Among the several extraction and clean-up procedures tested, ultrasonic extraction followed by alumina cartridge clean-up was the preferred method, yielding recoveries between 72 and 100% and limits of detection between 0.22 and 0.71 ng/g dry weight. The performance of the method was tested to determine PAHs in naturally contaminated samples.; The authors wish to thank Fundação da Ciência e Tecnologia (Portugal) for the scholarship SFRH/BD/11970/2002. This work was supported by the European Union (EU) through "Integrate modelling of the river-sediment-soil-groundwater system; advanced tools for the management of catchment areas and river basins in the context of global change" (AQUATERRA...

Determination of antimicrobials in sludge from infiltration basins at two artificial recharge plants by pressurized liquid extraction–liquid chromatography–tandem mass spectrometry

Díaz-Cruz, M. Silvia; López de Alda, Miren; Barceló, Damià
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 162 bytes; application/msword
ENG
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96.57%
11 pages, 4 figures, 4 tables.-- PMID: 16822516 [PubMed].-- Printed version published Oct 13, 2006.-- Issue title: 9th International Symposium on Hyphenated Techniques in Chromatography and Hyphenated Chromatographic Analyzers (York, UK, Feb 8-10, 2006).; This work describes the optimization of a multi-residue analytical approach for the simultaneous determination of 11 antimicrobials (9 sulphonamides and 2 penicillins) in sludge from infiltration basins. The method is based on pressurized liquid extraction (PLE) followed by solid-phase extraction (SPE) for pre-concentration and purification, and analysis by liquid chromatography–tandem mass spectrometry using electrospray in the positive ionization mode (LC–(ESI+)–MS/MS). Limits of detections (LODs) between 1 pg/g and 0.2 ng/g and limits of quantifications (LOQs) between 5 pg/g and 0.6 ng/g were achieved. Good recovery values (57.6–104%) were obtained for sulfamethazine, sulfapyridine, sulfadiazine and sulfamethoxypyridazine, while medium recovery values (14–47%) were afforded for sulfadimethoxine, sulfathiazole and sulfamethoxazole. However, only a poor recovery (<1%) could be possible for both penicillins and two sulphonamides, namely nafcillin, dicloxacillin, sulfisoxazole and sulfamethizole. These low recoveries were attributed to the presence of ionic suppression effects (even after thorough extraction and purification) rather than to an inefficient extraction. The method developed was applied to the analysis of sludge samples from the infiltration basins of two artificial recharge plants located in Sweden and Denmark. All target compounds were found to be present in at least one sample. Sulfadimethoxine...

Pressurized liquid extraction of selected molecular biomarkers in deep sea sediments used as proxies in paleoceanography

Calvo, Eva; Pelejero, Carles; Logan, Graham A
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
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Pressurized liquid extraction has been performed on a suite of deep-sea sediments to assess its capability as an extraction technique in the analysis of molecular biomarkers used in paleoceanography. Specific compounds assessed comprise long-chain alkenones, n-alkanes, n-alcohols and, additionally, one diol and one keto-ol. These have been extracted by both pressurized liquid extraction and ultrasonication for comparison. One key result is that the U37K′ index (based on the degree of unsaturation of the alkenones and used as a paleothermometer in paleoceanography) remains intact after both extraction techniques. In terms of biomarker concentrations, which are often used to qualitatively assess changes in marine productivity and/or terrigenous inputs, pressurized liquid extraction is substantially more efficient than ultrasonication, providing higher amounts of extracted constituents, particularly for polar compounds.