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Determination of apramycin in oral soluble powder by a HPLC method using pre-column derivatization with o-phthalaldehyde and UV detection

ANTUNES, Elisabete de Almeida Barbosa; LOURENÇO, Felipe Rebello; PINTO, Terezinha de Jesus Andreoli
Fonte: Universidade de São Paulo, Faculdade de Ciências Farmacêuticas Publicador: Universidade de São Paulo, Faculdade de Ciências Farmacêuticas
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
362.80605%
A high-performance liquid chromatographic method employing pre-column derivatization with o-phthalaldehyde (OPA) and 2-mercaptoacetic acid was developed for the determination of apramycin, an aminoglycoside antibiotic used in veterinary medicine, in the oral soluble powder form. The chromatographic separation was done by ion-pair HPLC using a C18 reversed-phase column, Synergy Hydro (150 mm x 4.6 mm x 4 µm) and mobile phase composed of 0.005 mol/L sodium octanosulfonate in a mixture of acetonitrile: water: acetic acid (45:55:2) (v/v/v) with a flow rate of 1.0 mL/min; the UV detector was operated at 332 nm. The developed method was validated according to official compendia guidelines, having demonstrated robustness, selectivity and linearity for the concentration range of 0.02 to 0.05 mg/mL, precision (with RSD < 2.0% both for intra and inter-day precision) accuracy (average recuperation of 99.33%) and detectivity (quantification and detection limits of 0.08 and 0.02 µg/mL, respectively). Three batches of commercial apramycin oral soluble powder were analyzed by both the proposed method and the official microbiological method, where all the results obtained were in the acceptable range (95% to 105% of labeled value of apramycin). Both methods were statistically compared by the t test...

Optimization of in situ derivatization SPME by experimental design for GC-MS multi-residue analysis of pharmaceutical drugs in wastewater

GOMES, Paulo Clairmont Feitosa de Lima; BARLETTA, Juliana Yamashita; NAZARIO, Carlos Eduardo Domingues; SANTOS-NETO, Alvaro Jose; WOLFF, Marya Anne Von; CONEGLIAN, Cassiana Maria Reganhan; UMBUZEIRO, Gisela Aragao; LANCAS, Fernando Mauro
Fonte: WILEY-BLACKWELL Publicador: WILEY-BLACKWELL
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
370.91004%
This paper presents the development of a procedure, which enables the analysis of nine pharmaceutical drugs in wastewater using gas chromatography-mass spectrometry (GC-MS) associated with solid-phase microextraction (SPME) for the sample preparation. Experimental design was applied to optimize the in situ derivatization and the SPME extraction conditions. Ethyl chloroformate (ECF) was employed as derivatizing agent and polydimethylsiloxane-divinylbenzene (PDMS-DVB) as the SPME fiber coating. A fractional factorial design was used to evaluate the main factors for the in situ derivatization and SPME extraction. Thereafter, a Doehlert matrix design was applied to find out the best experimental conditions. The method presented a linear range from 0.5 to 10 mu g/L, and the intraday and interday precision were lower than 16%. Applicability of the method was verified from real influent and effluent samples of a wastewater treatment plant, as well as from samples of an industry wastewater and a river.; CAPES; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); CNPq; Fapesp[07/03844-4]; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Fapesp[05/59360-0]

From Sample Processing to Quantification: A Full Electrochemical Approach for Neutral Analyte Derivatization, Capillary Electrophoresis Separation, and Contactless Conductivity Detection

Ferreira Santos, Mauro Sergio; Lopes, Fernando Silva; Rajh Vidal, Denis Tadeu; do Lago, Claudimir Lucio; Gutz, Ivano Gebhardt Rolf
Fonte: AMER CHEMICAL SOC; WASHINGTON Publicador: AMER CHEMICAL SOC; WASHINGTON
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
370.91004%
A thin-layer electrochemical flow cell coupled to capillary electrophoresis with contactless conductivity detection (EC-CE-(CD)-D-4) was applied for the first time to the derivatization and quantification of neutral species using aliphatic alcohols as model compounds. The simultaneous electrooxidation of four alcohols (ethanol, 1-propanol, 1-butanol, and 1-pentanol) to the corresponding carboxylates was carried out on a platinum working electrode in acid medium. The derivatization step required 1 min at 1.6 V vs. Ag/AgCl under stopped flow conditions, which was preceded by a 10 s activation at 0 V. The solution close to the electrode surface was then hydrodynamically injected into the capillary, and a 2.5 min electrophoretic separation was carried out. The fully automated flow system operated at a frequency of 12 analyses per hour. Simultaneous determination of the four alcohols presented detection limits of about 5 x 10(-5) mol As a practical application with a complex matrix, ethanol concentrations were determined in diluted pale lager beer and in nonalcoholic beer. No statistically significant difference was observed between the EC-CE-(CD)-D-4 and gas chromatography with flame ionization detection (GC-FID) results for these samples. The derivatization efficiency remained constant over several hours of continuous operation with lager beer samples (n = 40).; CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico...

Biopolímeros modificados: aspectos de derivatização de celulose sob condições homogêneas de reação; Modified biopolymers: aspects of cellulose derivatization under homogeneous reaction conditions

Fidale, Ludmila de Carvalho
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 20/12/2010 PT
Relevância na Pesquisa
370.91004%
Esta tese tem como objetivo a derivatização da celulose sob condições homogêneas de reação, através de um método simples, reprodutível e eficiente. As três etapas de derivatização da celulose (ativação, dissolução, e reação) foram estudadas com ênfase na relação entre a estrutura do biopolímero, as condições da reação e as propriedades dos derivados obtidos. Foi realizado estudo do intumescimento de celuloses (microcristalina, algodão, eucalipto, algodão mercerizado e eucalipto mercerizado) em solventes próticos e apróticos. O intumescimento foi correlacionado com as propriedades dos solventes. Nos próticos, as celuloses nativas e mercerizadas foram sensíveis aos mesmos quatro descritores (acidez, basicidade, dipolaridade/polarizabilidade e volume molar), porém, a contribuição relativa dessas propriedades foi diferente, sendo que no caso da celulose MC e das nativas a dipolaridade/polarizabilidade foi mais significativo e para as celuloses mercerizadas o volume molar foi o descritor mais importante. Para o intumescimento em solventes apróticos, para as celuloses mercerizadas, boas correlações foram obtidas empregando apenas um descritor (dipolaridade/polarizabilidade). No intumescimento intracristalino...

Análise de estatinas em plasma humano por cromatografia gasosa acoplada à espectrometria de massas utilizando SPME e derivatização in situ no preparo de amostra; Analysis of statins in human plasma by gas chromatography / mass spectrometry using SPME and in situ derivatization in sample preparation

Sattolo, Natalia Meinl Schmiedt
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 18/03/2011 PT
Relevância na Pesquisa
370.91004%
A monitorização terapêutica permite a individualização do regime de dosagem, assegurando a eficácia clínica e minimizando os efeitos adversos dos fármacos prescritos. Atualmente, as estatinas têm sido monitoradas, pois, embora eficazes e muito utilizadas, apresentam alguns efeitos adversos não desejáveis. Neste trabalho, as técnicas SPME e cromatografia gasosa acoplada à espectrometria de massas (GC-MS) foram avaliadas para a análise de estatinas (fluvastatina, simvastatina e atorvastatina) em plasma humano para fins de monitorização terapêutica. As condições de extração e derivatização foram otimizadas empregando planejamento experimental e avaliando a influência dos principais parâmetros envolvidos. Para otimização das condições de extração avaliou-se parâmetros como tempo e temperatura de extração, pH, volume de solução tampão e força iônica; e para otimização das condições de derivatização avaliou-se parâmetros como volume de reagente derivatizante, volume de agente pareador iônico e pH. A extração foi realizada utilizando fibras de PDMS-DVB, e a dessorção feita termicamente no injetor do cromatógrafo a gás. O método desenvolvido foi validado segundo normas da ANVISA, apresentando linearidade na faixa de 20 a 500 ng mL-1...

Derivatização eletroquímica da álcoois num sistema em fluxo para determinação quantitativa por eletroforese capilar com detecção condutométrica sem contato; Electrochemical derivatization of alcohols in a flow system for quantitative determinations by capillary electrophoresis and contactless conductivity detection

Santos, Mauro Sergio Ferreira
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 29/10/2012 PT
Relevância na Pesquisa
375.06086%
A eletroforese capilar (CE) é uma técnica poderosa de separação que explora as diferenças na mobilidade de espécies iônicas sob efeito do campo elétrico. Não permite, contudo, separação de misturas de moléculas neutras, possível mediante formação de complexos com carga, derivatização química ou cromatografia eletrocinética micelar (MEKC). A derivatização eletroquímica tem sido usada em combinação com HPLC, entre outras técnicas, mas não ainda com CE e para fins quantitativos, como proposto e demonstrado nesta dissertação, em que se enfoca, como sistemas modelo, álcoois primários de cadeia curta e se recorre a sistema em fluxo designado de EC-CE-C4D, que consiste de uma célula eletroquímica acoplada com equipamento de eletroforese capilar provido de detector de condutividade sem contato direto com os eletrodos. O sistema EC-CE-C4D, inicialmente concebido para efetuar pré-concentração e redissolução eletroquímica de metais seguida de separação eletroforética, possibilitou também o monitoramento de produtos com carga, formados em processos eletrocatalíticos, fato que inspirou a investigação da aplicabilidade, também do sistema à derivatização eletroquímica de analitos neutros em iônicos ou ionizáveis. Inicialmente...

Optimization of in situ derivatization SPME by experimental design for GC-MS multi-residue analysis of pharmaceutical drugs in wastewater

GOMES, Paulo Clairmont Feitosa de Lima; BARLETTA, Juliana Yamashita; NAZARIO, Carlos Eduardo Domingues; SANTOS-NETO, Alvaro Jose; WOLFF, Marya Anne Von; CONEGLIAN, Cassiana Maria Reganhan; UMBUZEIRO, Gisela Aragao; LANCAS, Fernando Mauro
Fonte: WILEY-BLACKWELL Publicador: WILEY-BLACKWELL
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
367.63727%
This paper presents the development of a procedure, which enables the analysis of nine pharmaceutical drugs in wastewater using gas chromatography-mass spectrometry (GC-MS) associated with solid-phase microextraction (SPME) for the sample preparation. Experimental design was applied to optimize the in situ derivatization and the SPME extraction conditions. Ethyl chloroformate (ECF) was employed as derivatizing agent and polydimethylsiloxane-divinylbenzene (PDMS-DVB) as the SPME fiber coating. A fractional factorial design was used to evaluate the main factors for the in situ derivatization and SPME extraction. Thereafter, a Doehlert matrix design was applied to find out the best experimental conditions. The method presented a linear range from 0.5 to 10 mu g/L, and the intraday and interday precision were lower than 16%. Applicability of the method was verified from real influent and effluent samples of a wastewater treatment plant, as well as from samples of an industry wastewater and a river.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Determination of etimicin in rat plasma using 9-fluorenylmethyl chloroformate precolumn derivatization by HPLC with fluorescence detection

Chang,Xiaojuan; Yu,Zhengping
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2011 EN
Relevância na Pesquisa
362.80605%
A new and sensitive method was developed for the determination of the etimicin (ETM) using precolumn derivatization (PCD) with 9-fluorenylmethyl chloroformate (FMOC-Cl) by a reversed phase separation and subsequent fluorescence detection. The PCD conditions were fully optimized towards the lowest limit of detection. The chromatographic separation was carried out on an Agilent XDB-C8 column at 25 ºC using a constant flow rate of 1.0 mL min-1 and mobile phase of acetonitrile/water (87:13, v/v). The etimicin-FMOC-Cl derivative was monitored by fluorescent detection at λexcitation 265 nm and λemission 315 nm. Neomycin (NMC), a similar base structure compound with ETM, was used as an internal standard. The statistical evaluation of the method was examined and the method was found to be precise and accurate with a linearity range of 0.038-9.69 µg mL-1 (r > 0.9994). The intra- and inter-day precision studies showed good reproducibility with relative standard deviation (R.S.D.) less than 5%, and the relative recovery was 97.80-100.09 % (n = 3). The limit of detection (LOD) and lower limit of quantification (LLOQ) in plasma were 0.01 and 0.02 µg mL-1, respectively. A volume of 50 µL of plasma was sufficient for the determination of etimicin. The established method provides a reliable bioanalytical method to carry out etimicin pharmacokinetics in rat plasma.

Determination of acidic herbicides in water samples by in situ derivatization, single drop microextraction and gas chromatography-mass spectrometry

Araujo,Lilia; Prieto,Avismelsi; Troconis,María; Urribarri,Grilena; Sandrea,Williams; Mercado,Jair
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2011 EN
Relevância na Pesquisa
370.91004%
A method for the determination of trace amounts of acidic herbicides in water samples was developed. The analytical procedure involves in situ derivatization of analytes to their methyl esters with dimethyl sulfate, sampling using single drop microextraction (SDME) and gas chromatography-mass spectrometry (GC-MS). The effects of pH, ionic strength, extraction time, solvent of extraction as well as derivatization conditions were studied. Methyl esters were extracted using 2 µL of n-heptane. The response was linearly dependent on the concentration in the range 0.05-10.0 ng mL-1. Limits of detection were achieved at the level of 1.8-3.0 ng L-1. Derivatization-SDME/GC-MS analysis yielded good precision (RSD between 7.0 and 15.2%). The method was validated by analysis of spiked matrix samples.

A simple and efficient method for derivatization of glyphosate and AMPA using 9-fluorenylmethyl chloroformate and spectrophotometric analysis

Catrinck,Tereza C. P. G.; Dias,Amanda; Aguiar,Maria Clara S.; Silvério,Flaviano O.; Fidêncio,Paulo H.; Pinho,Gevany P.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2014 EN
Relevância na Pesquisa
362.80605%
This work presents the confirmation and optimization of the method for derivatization of glyphosate and aminomethylphosphonic acid (AMPA) using 9-fluorenylmethyl chloroformate (FMOC-Cl) evaluating the parameters: concentration of borate buffer and FMOC-Cl, homogenization time and of reaction, wavelength and solvent washing. The reaction was successfully promoted and the method is simple and easy to perform because it uses five minutes of homogenization and allows ultraviolet analysis immediately after the end of the reaction.

Determination of apramycin in oral soluble powder by a HPLC method using pre-column derivatization with o-phthalaldehyde and UV detection

Antunes,Elisabete de Almeida Barbosa; Lourenço,Felipe Rebello; Pinto,Terezinha de Jesus Andreoli
Fonte: Universidade de São Paulo, Faculdade de Ciências Farmacêuticas Publicador: Universidade de São Paulo, Faculdade de Ciências Farmacêuticas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2011 EN
Relevância na Pesquisa
362.80605%
A high-performance liquid chromatographic method employing pre-column derivatization with o-phthalaldehyde (OPA) and 2-mercaptoacetic acid was developed for the determination of apramycin, an aminoglycoside antibiotic used in veterinary medicine, in the oral soluble powder form. The chromatographic separation was done by ion-pair HPLC using a C18 reversed-phase column, Synergy Hydro (150 mm x 4.6 mm x 4 µm) and mobile phase composed of 0.005 mol/L sodium octanosulfonate in a mixture of acetonitrile: water: acetic acid (45:55:2) (v/v/v) with a flow rate of 1.0 mL/min; the UV detector was operated at 332 nm. The developed method was validated according to official compendia guidelines, having demonstrated robustness, selectivity and linearity for the concentration range of 0.02 to 0.05 mg/mL, precision (with RSD < 2.0% both for intra and inter-day precision) accuracy (average recuperation of 99.33%) and detectivity (quantification and detection limits of 0.08 and 0.02 µg/mL, respectively). Three batches of commercial apramycin oral soluble powder were analyzed by both the proposed method and the official microbiological method, where all the results obtained were in the acceptable range (95% to 105% of labeled value of apramycin). Both methods were statistically compared by the t test...

An Examination of Pentafluorobenzoyl Derivatization Strategies for the Analysis of Fatty Alcohols using Gas Chromatography/Electron Capture Negative Ion Chemical Ionization-Mass Spectrometry

Bowden, John A.; Ford, David A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
279.93496%
Gas chromatography/electron capture negative ion chemical ionization-mass spectrometry (GC/ECNICI-MS) combined with pentafluorobenzoyl derivatization (PFBoyl) is frequently used for the sensitive detection of fatty alcohols (FOH). However, this derivatization technique suffers from a lack of established reaction protocols, time-consuming reactions, and the presence of reagent artifacts or unwanted derivatization byproducts which can hinder analyte detection. Here, strategies are presented to reduce the problems associated with PFBoyl-derivatization, including 1) the optimization of reaction conditions (derivatization time and temperature) for a variety of PFBoyl-derivatized FOH, 2) an investigation of microwave-accelerated derivatization (MAD) as a rapid alternative heating mechanism for the PFBoyl-derivatization of FOH, and 3) an analysis of an alternative strategy employing a solvent extraction procedure post-derivatization to reduce the detrimental effects commonly associated with PFBoyl derivatization reagents. The optimal reaction conditions for the PFBoyl-derivatization of FOH was determined to be 60 °C for 45 min. The investigation in MAD demonstrated the potential of obtaining comparable PFBoyl-derivatizations to those obtained using traditional heating methods...

Rapid Inline Derivatization of Primary and Secondary Amine Containing Drugs by Capillary Electrophoresis with Laser-Induced Fluorescence

Turnquest, Britt E.
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica Formato: application/pdf
Relevância na Pesquisa
367.63727%
Despite the ongoing “war on drugs” the seizure rates for phenethylamines and their analogues have been steadily increasing over the years. The illicit manufacture of these compounds has become big business all over the world making it all the more attractive to the inexperienced “cook”. However, as a result, the samples produced are more susceptible to contamination with reactionary byproducts and leftover reagents. These impurities are useful in the analysis of seized drugs as their identities can help to determine the synthetic pathway used to make these drugs and thus, the provenance of these analytes. In the present work two fluorescent dyes, 4-fluoro-7-nitrobenzofurazan and 5-(4,6-dichlorotriazinyl)aminofluorescein, were used to label several phenethylamine analogues for electrophoretic separation with laser-induced fluorescence detection. The large scale to which law enforcement is encountering these compounds has the potential to create a tremendous backlog. In order to combat this, a rapid, sensitive method capable of full automation is required. Through the utilization of the inline derivatization method developed whereby analytes are labeled within the capillary efficiently in a minimum span of time, this can be achieved. The derivatization and separation parameters were optimized on the basis of a variety of experimentally determined factors in order to give highly resolved peaks in the fluorescence spectrum with limits of detection in the low µg/mL range.

Enantiomeric separation of ornithine in complex mixtures of amino acids by EKC with off-line derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate

Martínez Girón, Ana Belén; Domínguez Vega, Elena; García Ruiz, Carmen; Crego Navazo, Antonio Luis; Marina Alegre, María Luisa
Fonte: B. Chankvetadze and E. Francotte Publicador: B. Chankvetadze and E. Francotte
Tipo: info:eu-repo/semantics/article; PeerReviewed Formato: application/pdf
ENG
Relevância na Pesquisa
362.80605%
A new analytical methodology was developed by EKC enabling the fast enantiomeric separation of Ornithine in complex mixtures of amino acids. A previous derivatization step with 6-aminoquinolyl-Nhydroxysuccinimidyl carbamate (AQC) was achieved to enable the sensitive UV detection of amino acids as well as to make possible their interaction with the CDs employed as chiral selectors. A dual CD system containing an anionic and a neutral CD in phosphate buffer at acid pH showed a high resolving power allowing the enantiomeric separation of 18 protein amino acids and Orn. The method was applied to the analysis of fermented foods to investigate the extent of the presence of Orn enantiomers.

Development of an in-capillary derivatization method by CE for the determination of chiral amino acids in dietary supplements and wines

Martínez Girón, Ana Belén; García Ruiz, Carmen; Crego Navazo, Antonio Luis; Marina Alegre, María Luisa
Fonte: WILEY-VCH Publicador: WILEY-VCH
Tipo: Artigo de Revista Científica Formato: application/pdf
ENG
Relevância na Pesquisa
370.91004%
A fast in-capillary derivatization method by CE with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate was developed for the first time for the determination of amino acid enantiomers (arginine, lysine, and ornithine) in dietary supplements and wines. Because of the initial current problems due to the formation of precipitates into the capillary during the derivatization reaction, a washing step with an organic solvent as DMSO between injections was necessary. Different approaches were also investigated to enhance the sensitivity of detection. A derivatization procedure, where plugs of ACN, derivatizing agent (10mM 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate), and sample in borate (1:1 v/v) were injected in tandem (2, 3, and 6 s, respectively, at 50 mbar), was selected because it enabled to obtain the most sensitive and reproducible results. Appropriate analytical characteristics (linearity, LOD and LOQ, precision, absence of matrix interferences, and accuracy) were obtained for this method. Finally, the optimized method was successfully applied to the determination of the enantiomers of arginine, lysine, and ornithine in food samples of different complexities (dietary supplements and wines).; The authors thank the Ministry of Education and Science (Spain) and the Comunidad Autónoma de Madrid (Spain) for research projects CTQ2006-03849/BQU and S-0505/AGR- 0312...

Determination of perfluorocarboxylic acids in aqueous matrices by ion-pair solid-phase microextraction–in-port derivatization–gas chromatography–negative ion chemical ionization mass spectrometry

Alzaga Morales, Roberto; Bayona Termens, Josep María
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 22195 bytes; application/pdf
ENG
Relevância na Pesquisa
362.80605%
8 pages, 4 figures, 3 tables.-- PMID: 15296400 [PubMed].-- Printed version published Jul 9, 2004.; A rapid, selective and simple analytical procedure using tetrabutylammonium as ion pair in conjunction with solid-phase microextraction followed by in-port derivatization–GC–negative ion chemical ionization mass spectrometry was developed. The procedure allows an accurate determination of perfluoroalkylcarboxylic acids in aqueous samples at ng L−1 levels (i.e. method detection limit 20 ng L−1 for perfluorodecanoic acid) improving previous GC methods in terms of analysis time and sensitivity. Ammonia as reagent gas in the negative ion chemical ionization mass spectrometry increased the sensitivity at least 3-fold compared to methane for perfluorocarboxylic acid butyl esters. The developed procedure was successfully applied to effluents from wastewater treatment plants (i.e. 0.05–8.2 μg L−1) and harbor seawaters.; This work was partly funded by the 5th Framework Program of the European Union IMSIS project (EVK1-CT-1999-00042) and the Spanish Ministry of Science and Technology (REN2001-1117).; Peer reviewed

Determination of linear alkylbenzensulfonates in aqueous matrices by ion-pair solid-phase microextraction-in-port derivatization-gas chromatography-mass spectrometry

Alzaga Morales, Roberto; Peña, Araceli; Ortiz Vera, Laura; Bayona Termens, Josep María
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 22195 bytes; application/pdf
ENG
Relevância na Pesquisa
362.80605%
10 pages, 4 figures, 2 tables.-- PMID: 12885051 [PubMed].-- Printed version published May 30, 2003.-- Issue title: 'ExTech 2002 - Advances in Extraction Technologies'.; Trace determination (low ng/ml) of linear alkylbenzensulfonates (LASs) in water was achieved by solid-phase microextraction (SPME) of ion-pairs formed with tetrabutylammonium. This ion-pairing reagent served two purposes. First, it allowed the extraction of LAS with the polydimethylsiloxane fiber by counterion association and second, the derivatization of the formed LAS ion pairs in the GC injection port at 300 °C to form the corresponding sulfonated butyl esters. The methodology developed allows the isomer specific determination of LAS at low detection limits (0.16–0.8 ng/ml), depending on the alkyl chain lengths of LASs with RSDs of 10–12%. Furthermore, the developed methodology was applied to urban wastewater and sea water and compared with a solid-phase extraction (SPE) method (e.g. C18 and strong anion-exchange sorbent) to obtain concordant values for urban wastewater. Moreover, the developed SPME methodology overcame the procedural blank and matrix-dependent recoveries found in the SPE methodologies at low LAS concentrations.; Financial support was obtained from the Fifth Framework Program of European Union (EVK3-CT-2000-00577) and the Spanish Ministry of Science and Technology (2FD1997-1298-CO2-02).; Peer reviewed

Determination of apramycin in oral soluble powder by a HPLC method using pre-column derivatization with o-phthalaldehyde and UV detection

Antunes, Elisabete de Almeida Barbosa; Lourenço, Felipe Rebello; Pinto, Terezinha de Jesus Andreoli
Fonte: Universidade de São Paulo. Faculdade de Ciências Farmacêuticas Publicador: Universidade de São Paulo. Faculdade de Ciências Farmacêuticas
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; ; Formato: application/pdf
Publicado em 01/06/2011 ENG
Relevância na Pesquisa
362.80605%
Foi desenvolvido um método por cromatografia líquida alta eficiência empregando derivatização pré-coluna com o-ftalaldeído (OPA) e ácido mercaptoacético para determinação de apramicina, um antibiótico aminoglicosídeo de uso veterinário, em pó oral solúvel. A separação cromatográfica foi feita por fase reversa com pareamento iônico utilizando-se coluna Synergy Hydro C18 (150 x 4,6 mm x 4 µm) e fase móvel composta por octanossulfonato de sódio 0,005 mol/L em mistura de acetonitrila:água:ácido acético nas proporções 45:55:2 (v/v/v), numa vazão de 1.0 mL/min; efetuou-se detecção por UV a 332 nm. O método foi validado de acordo com os compêndios oficiais e demonstrou robustez, seletividade, linearidade na faixa de 0,02 a 0,05 mg/mL, precisão (com DPR < 2,0% tanto para a precisão intra-dia quanto para a precisão inter-dia), exatidão (recuperação média de 99,33%) e detectabilidade (limite de quantificação e de detecção iguais a 0,08 e 0,02 µg/mL, respectivamente). Analisaram-se 3 lotes de apramicina pó oral solúvel pelo método proposto e pelo método microbiológico oficial e todos os resultados obtidos estavam dentro do limite de aceitação (95%-105% valor rotulado de apramicina). Ambos os métodos foram comparados estatisticamente pelo teste t...

Identification and Quantification of Aldehydes in Mezcal by Solid Phase Microextraction with On-fiber Derivatization - Gas Cromatography

Medina Valtierra,Guadalupe; Juárez Ciprés,Rocío; Peña Álvarez,Araceli
Fonte: Sociedad Química de México A.C. Publicador: Sociedad Química de México A.C.
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2011 EN
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A headspace solid phase microextraction with on fiber derivatization procedure followed by gas chromatography and flame ionization detection was applied for the determination of aldehydes in mezcal. A derivatization agent o-(2,3,4,5,6-pentafluorobenzyl) hy-droxylamine (PFBHA) was adsorbed onto a Polydimethylsiloxane/ divinyl benzene (PDMS/DVB, 65 μιη) fiber and exposed to the head-space of a vial with a mezcal sample. The aldehydes selectively reacted with PFBHA, and the oximes were desorbed into a gas chromatograph injection port. Identification of the compounds was performed with standards and confirmed by mass spectrometry. The procedure was applied to the analysis of 13 mezcal samples from different agave varieties. Calibration curves for acetaldehyde and furfural showed good linearity (r² > 0.99) in the studied concentration range, 1-9 μg/mL for acetaldehyde and 0.5-1 μg/mL for furfural in the diluted mezcal samples. Good precision was obtained for acetaldehyde, CV <6.3% and furfural <10%. Based on the standard for tequila NOM-006-SCFI-2005, all mezcal samples showed concentrations of acetaldehyde within the norm, while 2 mezcals exceeded the allowed limit for furfural.

Improved derivatization protocol for simultaneous determination of alkylphenol ethoxylates and brominated flame retardants followed by gas chromatography-mass spectrometry analyses

Chokwe,TB; Okonkwo,JO; Sibali,LL; Ncube,EJ
Fonte: Water SA Publicador: Water SA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2015 EN
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An improved derivatization protocol for the simultaneous determination of alkylphenol ethoxylates and brominated flame retardants with heptafluorobutyric anhydride under triethylamine amine base was investigated. The derivatization reaction was completed in 30 min at 50°C using hexane as solvent. Under these conditions, it was observed that alkylphenol ethoxylates and tetrabromobisphenol A were derivatized successfully in the presence of hexabromocyclododecane, lower congeners of polybrominated biphenyls and polybrominated diphenyl ethers. The improved protocol was applied to recovery of analytes of interest from simulated water samples after solid phase extraction. The recoveries achieved were above 60%. The limit of detection and limit of quantification ranged from 0.01-0.20 μg/ℓ and 0.05-0.66 μg/ℓ respectively.