Sample records for gas chromatography
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1

Determinação de fenol urinário por cromatografia em fase gasosa em trabalhadores que utilizam resinas fenólicas em fundições/ Determination of urinary phenol by gas chromatography in workers using phenolic resins in foundries

Peixe, Tiago Severo; Nascimento, Elizabeth de Souza; Della Rosa, Henrique Vicente
2006-06-01

Resumo em português O fenol é utilizado na indústria como agente desinfetante no preparo de resinas fenólicas e pigmentos de tintas. Apresenta-se no estado sólido à temperatura ambiente, com coloração fracamente rósea, odor acre e higroscópico. Na exposição ocupacional aguda o composto pode levar a lesões eritematosas e, cronicamente, afetar a maturação celular no compartimento medular ósseo devido à formação de quinonas livres e 1,4-benzoquinona, proveniente do metabolismo (mais) hepático da hidroquinona via CYP2E1. A monitorização biológica possui relevância nas situações de exposições ocupacionais. Para tal, utiliza-se o fenol urinário, considerado bioindicador de exposição a este composto. O objetivo do presente trabalho foi validar uma técnica de extração líquido-líquido para quantificar o fenol urinário, por meio da cromatografia em fase gasosa com detetor de ionização por chama (CG/DIC) em urina de trabalhadores expostos ao fenol em fundições. O método mostrou-se linear de 5 a 200 µg/mL; coeficiente de regressão linear (r²) de 0,999; limites de detecção e quantificação 2,0 e 5,0 µg/mL, respectivamente; precisão intra-ensaio entre 4,5 e 8,9% e inter-ensaio entre 5,7 e 14,2%; exatidão entre 6,2 e 11,9% e recuperação superior a 87%. O método demonstrou ser simples e rápido. Amostras provenientes de trabalhadores expostos ao fenol foram analisadas comprovando a aplicação da técnica na monitorização biológica. Resumo em inglês Phenol is used as an industrial chemical, disinfectant agent, in the preparation of phenolic resins and paint pigments. When in solid state, it shows a light pink color, ocre odor, and is hygroscopic. In acute occupational exposure, the compound can produce erythemic injuries and burn sensation and, chronically, affect the cellular maturation of bone marrow due the free quinones and 1,4-benzoquinone, deriving from hepatic metabolism of the hydroquinone by P450 isozyme (CY (mais) P2E1). The biological monitoring is important in occupational exposure situations. So, urinary phenol, considered the biological indicator of phenol exposure has to be determined. The aim of this work was to validate a method for urinary phenol quantification, using liquid-liquid extraction. Gas chromatography with flame ionization detector (GC/FID) was used in this method. The analytical procedure showed linearity in the dynamic range of the assay from 5 - 200 µg/mL. The limits of detection (LOD) and quantification (LOQ) were: 2.0 and 5.0 µg/mL, respectively. Intra-assay precision coefficient was between 4.5 - 8.9% and the inter-assay precision coefficient was between 5.7 - 14.2%. The accuracy coefficient was between 6.2 - 11.9%. Recovery values were higher than 87%. The coefficient of correlation was 0.999. The method is simple, rapid and efficient. Urine samples from workers exposed to phenolic resins were analyzed to show the method application in biological monitoring.

Scientific Electronic Library Online (Portuguese)

2

Determinação de efedrinas em urina por cromatografia em fase gasosa (CG/DNP) para o controle da dopagem no esporte/ Gas chromatographic method for the determination of ephedrines in urine for doping control purposes

Garcia, Paula Rodrigues; Yonamine, Mauricio; Moreau, Regina Lúcia de Moraes
2005-09-01

Resumo em português Efedrinas são aminas simpatomiméticas componentes de diversas especialidades farmacêuticas, utilizadas no tratamento de doenças respiratórias devido à sua ação descongestionante e broncodilatora. Atualmente, diversos produtos comercializados como suplementos nutricionais contêm efedrinas e são amplamente utilizados no meio esportivo, com o objetivo de facilitar a queima de gorduras e melhorar o desempenho. Entretanto, o uso indiscriminado destas substâncias pod (mais) e acarretar série de efeitos tóxicos como hipertensão, taquicardia, cefaléia e tremores. Devido à sua ação psicoestimulante, foram incluídas na lista de substâncias proibidas nas atividades esportivas pelo Comitê Olímpico Internacional (COI) e estabelecidas concentrações na urina para o controle da dopagem (efedrina e metilefedrina: 10 µg/mL). O presente trabalho teve como objetivo a validação de um método para quantificação de efedrinas, por cromatografia em fase gasosa acoplada a detetor de nitrogênio/fósforo (CG/DNP), em amostras de urina com a finalidade de controle da dopagem. O método consistiu em extração líquido-líquido e posterior derivação das efedrinas com anidrido trifluoroacético, e demonstrou ser simples e prático, apresentando linearidade nas faixas de concentração estudadas. Amostras de urina de voluntários que relataram uso de efedrinas foram submetidas à análise pelo método proposto. Resumo em inglês Ephedrines are sympathomimetic amines present in many pharmaceutical preparations used in the treatment of respiratory diseases due to their actions against broncospasm and congestion. Nowadays, several products sold as nutritional supplements contain ephedrines and are widely used in a diverse range of sports as weight loss aids and enhancement of athletic performance. However, the abuse of ephedrines may lead to a number of adverse effects including hypertension, headac (mais) he, tachycardia and seizure. Due to their CNS stimulating action, ephedrines are included in the prohibited list of substances by the International Olympic Committee (IOC). Urinary threshold concentrations were established (ephedrine and methylephedrine >10 µg/mL). The aim of this work was to develop and validate a method for the simultaneous determination of ephedrines present in urine samples for doping purposes by gas chromatography with nitrogenous-phosphorous detector (GC/NPD). The method was based on a liquid-liquid extraction of alkalinized urine and further derivatization with trifluoroacetic anhydride (TFA). The validated method showed to be simple, practical and linear at the studied concentrations range. Urine samples collected from volunteers, who reported the use of ephedrines, were submitted to the proposed method.

Scientific Electronic Library Online (Portuguese)

3

Análise de praguicidas organofosforados em água por extração em fase sólida (SPE) utilizando discos C18 e cromatografia em fase gasosa: avaliação da contaminação do reservatório de Furnas (MG-Brasil)/ Analysis of organophosphorus pesticides in water using SPE C18 disks and gas chromatography: evaluation of Furnas dam contamination

Santos Neto, Alvaro José dos; Siqueira, Maria Elisa Pereira Bastos de
2005-10-01

Resumo em inglês Solid phase extraction (SPE) in C18 disks has been optimized and validated for extraction of 5 organophosphorus (OP) pesticides in water. Extraction has been followed by separation and detection by gas chromatography/flame photometry. Excellent linearity was obtained for all compounds (r greater than 0.99), with CVs between 1.0-6.9%, recoveries between 73-95% and quantification limits between 2.5-5.0 µg L-1. Samples from Furnas dam were analyzed monthly during one year and 10% showed OP pesticide residues.

Scientific Electronic Library Online (Portuguese)

4

Determinação de traços de Co e Co2 "em linha" por cromatografia em fase gasosa/ Determination of Co and Co2 on line (at low ppbV levels) by gas chromatography

Jesus, Rosangela Novaes de; Andrade, Jailson B. de
1998-07-01

Resumo em inglês The present work describes a rapid and sensitive method for the determination of carbon monoxide and carbon dioxide at low concentration levels, on line, in ethylene and hydrogen lines. These gases were separated in a column filled with Porapak Q, converted to methane and quantified by a flame ionization detector. Some modifications were made in the injection system and in the lines of the carrier gas. The detection limits of 2,6 ppbV and 4,85 ppbV for CO and CO2, respectively, were reached after modifications.

Scientific Electronic Library Online (Portuguese)

5

Validação de método para determinação de 3,4-metilenodioximetanfetamina (MDMA) em comprimidos de ecstasy por cromatografia em fase gasosa/ Validation of a gas-chromatographic method for the determination of 3,4-methylenedioxymethamphetamine(MDMA) in ecstasy tablets

Lapachinske, Silvio Fernandes; Yonamine, Mauricio; Moreau, Regina Lucia de Moraes
2004-03-01

Resumo em português O ecstasy é comercializado, de maneira ilegal, normalmente sob a forma de comprimidos, com cores, aspectos, dimensões e logotipos variados. Quimicamente, é a metilenodioximetanfetamina (MDMA), um composto sintético com propriedades estimulante central e alucinogênicas. Devido à grande expansão do abuso de ecstasy, também tem aumentado o número de casos de intoxicações, decorrentes diretamente da droga (MDMA e análogas) e/ou de eventuais adulterantes. Algumas s (mais) ubstâncias análogas à MDMA, já identificadas em comprimidos de ecstasy são: metilenodioxietilanfetamina (MDEA), metilenodioxianfetamina (MDA), metanfetamina e anfetamina. Como possíveis adulterantes, geralmente são encontradas cafeína e efedrinas. O objetivo deste trabalho foi a validação de um método analítico para quantificar a MDMA em comprimidos ou cápsulas de ecstasy, através da cromatografia em fase gasosa com detector de nitrogênio/fósforo (GC/NPD). Além disso, substâncias análogas à MDMA e adulterantes também foram identificados. O método, que consiste na dissolução direta da amostra em metanol, centrifugação e diluição do sobrenadante, demonstrou ser simples, rápido e eficiente. Os limites de detecção e quantificação para a MDMA foram respectivamente de 1,5 e 3,0 mg/100 mg de comprimido. Amostras de comprimidos e cápsulas apreendidos como sendo ecstasy provenientes de 25 lotes foram analisadas, apresentando considerável variabilidade na composição e na quantidade de MDMA. Resumo em inglês Ecstasy is illegally commercialized in the form of tablets with different aspects, colors, sizes, and logotypes. Chemically, ecstasy is 3,4-methylenedioxymethamphetamine (MDMA), a synthetic compound with stimulant and hallucinogenic proprieties. Due to the great expansion of ecstasy abuse, the number of cases of intoxications by MDMA, analogs and eventual adulterant compounds has also increased. Some MDMA analog substances, such as 3,4-methylenedioxyethylamphetamine (MDEA (mais) ), 3,4-methylenedioxyamphetamine (MDA), methamphetamine and amphetamine have already been identified in ecstasy tablets. Caffeine and ephedrines are the most common adulterants also found. The aim of this paper is to describe the validation of an analytical method to quantify MDMA in ecstasy tablets and capsules. Gas-chromatography with nitrogen/phosphorous detector was used in the method, which consisted in the direct dissolution of the sample in methanol, centrifugation and convenient dilution of the supernatant. Analog substances to MDMA and adulterants were also identified. The limits of detection and quantification (LOQ and LOD) for MDMA were 1.5 and 3.0 mg/100 mg of tablet. Samples from 25 lots of tablets seized in the city of São Paulo were analyzed showing a considerable variability in composition and quantity of MDMA.

Scientific Electronic Library Online (Portuguese)

6

Determinação de metil-etil-cetona em amostras de urina com amostragem por micro extração em fase sólida (MEFS) em headspace associada à cromatografia gasosa com detector de ionização de chama (CG-DIC)/ Determination of methyl ethyl ketone in urine samples by headspace solid phase micro extraction (SPME) sampling associated to gas chromatography with flame-ionization detectoR (GC-FID)

Antunes, Marina Venzon; Linden, Rafael
2008-01-01

Resumo em inglês Methyl ethyl ketone (MEK) is a solvent commonly used in chemical, paint and shoe industry. The aim of this study was to develop and validate a method for urinary quantification of MEK, employing headspace solid phase micro extraction sampling (SPME) coupled to gas chromatography with flame ionization detection (GC-FID). The calibration curve (y=4.6851x-0.0011) presented good linearity with r²=0.9993. Accuracy (94-109%), intra-assay precision (4.07-5.91%) and inter-assay (mais) precision (3.03-5.62%) were acceptable. The quantification limit was 0.19 mg/L. This low cost method can be used routinely in the biological monitoring of occupational exposure to MEK, according to the requirements of the Brazilian legislation.

Scientific Electronic Library Online (Portuguese)

7

Determinação de etanol e voláteis relacionados em sangue e fluido oral por microextração em fase sólida em headspace associada à cromatografia gasosa com detector de ionização em chama/ Determination of ethanol and related volatile compounds in blood and oral fluid by headspace solid-phase micro extraction associated to gas chromatography with flame-ionization detector

Feltraco, Lílian de Lima; Antunes, Marina Venzon; Linden, Rafael
2009-01-01

Resumo em inglês The aim of this study was to validate a method for the determination of acethaldehyde, methanol, ethanol, acetone and isopropanol employing solid-phase microextraction associated to gas chromatography with flame ionization detection. The operational conditions of SPME were optimized by response surface analysis. The calibration curves for all compounds were linear with r² > 0.9973. Accuracy (89.1-109.0%), intra-assay precision (1.8-8.5%) and inter-assay precision (2.2-8. (mais) 2%) were acceptable. The quantification limit was 50 µg/mL. The method was applied to the meaurement of ethanol in blood and oral fluid of a group of volunteers. Oral fluid ethanol concentrations were not directly correlated with blood concentrations.

Scientific Electronic Library Online (Portuguese)

8

Análise de resíduos de agrotóxicos em tomates empregando dispersão da matriz em fase sólida (DMFS) e cromatografia gasosa/ Analysis of pesticide residue in tomato using matrix solid-phase dispersion (MSPD) and gas chromatography

Pinho, Gevany P.; Neves, Antônio A.; Queiroz, Maria Eliana L. R.
2009-01-01

Resumo em inglês This work was aimed on optimization of the matrix solid-phase dispersion (MSPD) technique using gas chromatography for analyzing residues of chlorpyriphos, λ-cyhalothrin, cypermethrin and deltamethrin in tomatoes. The results showed that silica was more efficient for the clean up of extracts, but florisil provided the highest recovery rates. A 2³ complete factorial design was carried out to evaluate the absorbent/sample ratio, presence of co-column (silica) and ultr (mais) asonic bath on the extraction rate. The percentage of extraction of the pesticides chlorpyriphos, λ-cyhalothrin, cypermethrin and deltamethrin were 64.7, 88.3, 99.2 and 89.2%, respectively, with relative standard deviations below 5%.

Scientific Electronic Library Online (Portuguese)

9

Aplicação de métodos quimiométricos na caracterização de charutos utilizando extração por dispersão da matriz em fase sólida e análise por cromatografia gasosa acoplada à espectrometria de massas/ Aplication of chemometrics methods in characterization of cigar using matrix solid phase dispersion and gas chromatography-mass spectrometry

Prata, Vanessa de Menezes; Emídio, Elissandro Soares; Dórea, Haroldo Silveira
2011-01-01

Resumo em inglês In this work, the organic compounds of cigar samples from different brands were analyzed. The compound extraction was made using the matrix solid-phase dispersion (MSPD) technique, followed by gas chromatography and identification by mass spectrometry (GC-MS) and standards, when available. Thirty eight organic compounds were found in seven different brands. Finally, with the objective of characterizing and discriminating the cigar samples, multivariate statistical analyse (mais) s were applied to data, e.g.; principal component analysis (PCA) and hierarchical cluster analysis (HCA). With such analyses, it was possible to discriminate three main groups of three quality levels.

Scientific Electronic Library Online (Portuguese)

10

Determinação simultânea dos ácidos hipúrico e metil-hipúrico urinários por métodos cromatográficos: comparação entre cromatografia líquida de alta eficiência e cromatografia gasosa capilar/ Simultaneous determination of urinary hyppuric and methylhyppuric acids through chromatographic methods: comparation between high performance liquid chromatography and capilary gas chromatography

Silva, Zelaine Lima; Silveira, Josianne Nicácio; Jacinto, Márcio; Amorim, Leiliane Coelho André; Alvarez-Leite, Edna Maria
2002-06-01

Resumo em português O presente trabalho foi realizado objetivando-se comparar a eficiência de dois métodos analíticos, um por cromatografia líquida de alta eficiência (CLAE) e outro por cromatografia em fase gasosa com coluna capilar (CG), na determinação conjunta do ácido hipúrico (AH) e ácido metil-hipúrico (AMH) em urina de indivíduos expostos ocupacionalmente ao tolueno e xileno. Após a validação analítica foi observado que o método CLAE apresentou melhores precisão int (mais) ra e interensaio, porcentagem de recuperação e sensibilidade. Amostras de urina de trabalhadores expostos aos dois solventes em fábrica de tintas-látex foram analisadas pelos dois métodos validados e os resultados avaliados estatisticamente. Não se encontrou diferença significativa entre os valores de AH superiores a 1,0 g/g de creatinina, quando determinados pelos dois métodos cromatográficos. Esta similaridade não foi repetida quando os níveis de AH eram inferiores a 1,0 g/g de creatinina. Os valores de AMH nas amostras analisadas estavam, na maioria das vezes, abaixo do limite de deteção, razão pela qual não foi realizada a comparação estatística entre os mesmos. Resumo em inglês High performance liquid chromatography and capillary gas chromatography were compared for simultaneous measurement of hyppuric and methyl hyppuric acids in urine of workers co-exposed to toluene and xilene. Quantitative advantages offered by HPLC over capillary GC method are observed: better average recovery, wider dynamic interval in calibration curve and lower detection and quantification limits mainly when MHA measurement was performed. No significant difference was fo (mais) und between the values of HA higher than 1.0 g/g creatinine measured by the two chromatographic procedures. Regarding to MHA concentration the methods gave similar results and there was no significant difference between the values.

Scientific Electronic Library Online (Portuguese)

11

Obtenção de ácidos graxos por cristalização do óleo de pescado fracionado por hidrólise enzimática/ Fatty acid isolation by crystallization of fish oil fractioned by enzymatic hydrolysis

Padilha, Márcia Elisa da Silva; Augusto-Ruiz, Walter
2010-03-01

Resumo em português Este trabalho teve por objetivo estabelecer um processo para obter e caracterizar os produtos da cristalização das frações do óleo de pescado hidrolisado com lipase pancreática. A hidrólise enzimática foi realizada em 60 minutos com uma concentração de substrato de 1262 mmols, 38 °C, pH 8 e com uma concentração de extrato enzimático de 7,647 mg.mL-1. Os produtos da hidrólise foram separados por cromatografia em coluna e caracterizados por cromatografia em c (mais) amada delgada e cromatografia em fase gasosa. A temperatura de cristalização foi controlada entre 5 °C e -18 °C. A fração TAG foi melhor cristalizada a 0 °C enquanto que as frações DAG + AGL e MAG foram cristalizadas a 5 °C. Foi observado que o ácido docosahexaenoico (DHA) concentra-se na fase líquida da fração DAG + AGL representando 97,17% em relação ao óleo de pescado. O ácido palmítico foi cristalizado na fração DAG, perfazendo aproximadamente 50% do total de ácidos graxos. Foi observado que os ácidos graxos insaturados de cadeia longa, principalmente o EPA, concentram-se na fase sólida da fração TAG, esses resultados sugerem que o processo combinado de hidrólise enzimática seguido de cristalização possibilita a obtenção destes ácidos graxos do óleo de pescado. Resumo em inglês The main objective of this work was to establish a process to characterize the crystallization products of fish oil fractions hydrolyzed with pancreatic lipase. Enzymatic hydrolysis was accomplished in a 60 minute hydrolysis employing a substrate concentration of 1262 mols, 38 °C, with an enzyme concentration (protein) of 7.647 mg.mL-1, pH 8. The hydrolysis products were separated by column chromatography, thin layer chromatography, and gas chromatography. The crystalliz (mais) ation temperature was controlled between 5 °C and -18 °C. The TAG fraction was best crystallized at 0 °C while the DAG + AGL and MAG fractions were crystallized at 5 °C. It was observed that docosahexaenoic acid (DHA) concentrated in the liquid phase of the DAG + AGL fractions represented 97.17 per cent of the fish oil. Palmitic acid was crystallized in the DAG fraction and comprised about 50 per cent of the total fatty acids. The long chain polyunsaturated fatty acids, mainly the EPA, are concentrated in the solid phase of the TAG fraction. The results suggest that the isolation of fatty acids from fish oil can be accomplished using a combination of enzymatic hydrolysis followed by crystallization.

Scientific Electronic Library Online (Portuguese)

12

Pirólise de resíduos poliméricos gerados por atividades offshore/ Pyrolysis of offshore solid wastes

Oliveira, Mara L. de; Cabral, Lucianna L.; Leite, Marcia C. A. M.; Marques, Mônica R. C.
2009-01-01

Resumo em português Resíduos plásticos gerados pelas atividades offshore da indústria de exploração e produção de óleo e gás, após caracterização por ensaio de identificação das classes poliméricas e análise térmica, foram pirolisados em atmosfera inerte a 450 °C. Os óleos pirolíticos foram caracterizados por espectrofotometria de infravermelho por transformada de Fourier (FTIR) e cromatografia em fase gasosa acoplada à espectrometria de massas (CG/EM), indicando a composição de parafinas, olefinas e aromáticos. Resumo em inglês Solid wastes from oil and gas offshore exploration and production activities, after characterization of polymeric classes and thermal identification analysis tests, were pyrolysed under an inert atmosphere at 450 °C. The pyrolysis oil was characterized by Fourier Transform Infrared Spectroscopy (FTIR) gas chromatography mass spectrometry (CG/EM), indicating high generation of paraffin, olefines and aromatics.

Scientific Electronic Library Online (Portuguese)

13

Estudo comparativo dos óleos voláteis de algumas espécies de Piperaceae/ Comparative study of the essential oils of some species of Piperaceae

Mesquita, J.M.O.; Cavaleiro, C.; Cunha, A.P.; Lombardi, J.A.; Oliveira, A.B.
2005-03-01

Resumo em português O presente trabalho teve por objetivo a análise comparativa dos óleos voláteis de espécies da família Piperaceae. As espécies estudadas foram as seguintes: Piper aduncum, P. amalago, P. arboreum, P. cernuum, P. hispidum, P. regnelii, P. submarginalum, P. vicosanum e Pothomorphe umbellata. A análise dos óleos voláteis foi efetuada pela combinação de técnicas de Cromatografia de Fase Gasosa (CG) e de Cromatografia de Fase Gasosa acoplada a Espectrometria de Mass (mais) a (CG/EM). A porcentagem de identificação dos constituintes nas análises dos óleos voláteis de Piper aduncum, P. amalago, P. vicosanum, P. submarginalum e Pothomorphe umbellata, atingiu valores superiores a 80%. Houve predominância de compostos de natureza sesquiterpênica nas composições químicas das espécies analisadas, com exceção de P. hispidum, P. submarginalum e P. vicosanum onde a predominância na composição foi de monoterpenos. Pelos dados apresentados observou-se que, dentre os compostos majoritários, os mais freqüentes, nas 9 espécies estudadas, foram beta-pineno (9/9) e espatulenol (9/9), seguidos por E-cariofileno (8/9), óxido de cariofileno (8/9), germacreno D (7/9), alfa-pineno (7/9) e limoneno (6/9). Pela primeira vez se relata a composição dos óleos voláteis de P. submarginalum e P vicosanum. Resumo em inglês Essential oils from various vegetal species of the Piperaceae family were analysed by Capillary Gas Chromatography (GC) and Gas Chromatography/Mass Spectrometry (GC/MS). The investigated species were: Piper aduncum, P. amalago, P. arboreum, P. cernuum, P. hispidum, P. regnelii, P. submarginalum, P. vicosanum and Pothomorphe umbellata. Over 80% of the essential oils compounds were identified by the qualitative and quantitative analysis. The analysed species showed the pred (mais) ominance of sesquiterpenoids, except for P. hispidum, P. submarginalum and P. vicosanum in which the predominant compounds were monoterpenoids. For the 9 studied species, the major compounds found in the oils were beta-pinene (9/9) and spathulenol (9/9), followed by the E-caryophyllene (8/9), caryophyllene oxide (8/9), germacrene D (7/9), alpha-pinene (7/9) and limonene (6/9).

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14

Otimização e validação de metodologia cromatográfica para determinação simultânea de composição monomérica em polímero biodegradável/ Optimization and validation of chromatographic method for simultaneous determination of monomeric composition in biodegradable polymer

Souza, J. L.; Santos, A. F. dos; Polese, L.; Crespi, M. S.; Ribeiro, C. A.
2006-01-01

Resumo em português O biopolímero poli(3-hidroxibutirato) PHB, importante pelas suas propriedades de biodegradabilidade e biocompatibilidade, pode apresentar melhores características termoplásticas quando estruturalmente modificado com anidrido maleico (AM). Para avaliar a proporção de anidrido maleico presente nos filmes de PHB com a proporção no intervalo de 0 a 20% de AM para o PHB, foram otimizadas as condições experimentais e determinados os principais parâmetros de validaçã (mais) o para a análise simultânea de derivados de PHB e AM, utilizando-se cromatografia em fase gasosa (GC). Os resultados demonstram que o procedimento analítico pode ser aplicado com confiabilidade. Resumo em inglês The poly(3-hydroxybutyrate) (PHB) are an important biopolymer with biodegradable and biocompatible properties. When PHB is submitted to structural modification with maleic anhydride (MA) is possible to obtain PHB with superior thermoplastic characteristics. A gas chromatography (GC) method has been optimized and validated for simultaneous determination of monomeric proportions (0 to 20% w/w in MA) in PHB/MA films. The results demonstrated that the analytical procedure is (mais) a consistent chromatographic method to identification and quantification from PHB and MA isoamilic esters derivatives.

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15

Desenvolvimento e validação de um método cromatográfico em fase gasosa para análise da 3,4-metilenodioximetanfetamina (ecstasy) e outros derivados anfetamínicos em comprimidos/ Development and validation of a gas chromatography method for determination of ecstasy and amphetamines derivatives in tablets

Lasmar, Marcelo Carvalho; Leite, Edna Maria Alvarez
2007-06-01

Resumo em português O uso abusivo das anfetaminas e seus derivados vêm aumentando dramaticamente nos últimos anos em diversas regiões do mundo, notando-se especial utilização do Ecstasy. A análise de amostras da droga apreendidas nas ruas evidenciou, além da presença de MDMA (3,4-metilenodioximetanfetamina), componente principal da droga, outras feniletilaminas, como a MDA (3,4-metilenodioxanfetamina) e MDEA (metilenodioximetiletilanfetamina) este último também conhecido como a dro (mais) ga Eve, ainda pouco difundida no Brasil. O objetivo do presente trabalho foi desenvolver e validar um método analítico confiável, prático e acessível aos laboratórios de toxicologia, de médio e pequeno porte, no Brasil e em países em desenvolvimento, para identificação separada do MDMA, MDA e MDEA. A cromatografia em fase gasosa utilizando-se coluna capilar e detector de ionização de chama foi a técnica escolhida. O método analítico apresentou para os três analitos de interesse, faixa ampla de linearidade (1,0 a 500,0 µg/mL); limites de quantificação de 1,0 µg/mL e coeficientes de variação intra e interensaio inferiores a 9,5%. Os limites de detecção estabelecidos foram 0,7 µg/mL, 0,8 µg/mL e 0,6 µg/mL, respectivamente para o MDMA, MDA e MDEA. O método foi seletivo na presença de epinefrina, cocaína, anfetamina, ácido acetilsalisílico, metanfetamina, ácido dietilbarbitúrico, p-aminobenzoil dietilbarbitúrico, paracetamol e cafeína. Resumo em inglês The abusive use of the amphetamine derivative ecsyasy in the world come increasing in the last years. Many tablets samples kept on the streets shown the presence not only of the MDMA- 3,4-methylenedioxymethamphetamine, the main drug component but also of the MDA - 3,4- methylenedioxyamphetamine and MDEA - 3,4-methylenedioxymethylethylamphetamine. The present study sought to develop and validate an analytical method for determination of MDMA, MDA and MDEA in tablets to be (mais) accessible for the most small or medium laboratories of toxicology of the development countries as Brazil. It was chosen for development and validation a gas chromatography method with flame ionization detection. The analytic validation results for MDMA, MDA and MDEA were linearity range of 1.0 to 500.0 µg/mL, intra and interassay coefficient of variation lower than 9.5% and quantification limit of 1.0 µg/mL. The detection limits were 0.7 µg/mL, 0.8 µg/mL and 0.6 µg/mL respectively to MDMA, MDA and MDEA. The method showed a good seletivity as the epinephrine, cocaine, amphetamine, methamphetamine, acethyl salicilic acid, diethyl barbituric acid, p-aminobenzoyl diethyl barbituric, paracetamol and caffeine presences did not interfere with the measurement of the three analytes.

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Ácidos orgânicos em aguardentes produzidas em alambique e em coluna/ Organic acids in sugarcane spirits' fractions produced in stills and columns

Serafim, Felipe Augusto Thobias; Buchviser, Silmara França; Galinaro, Carlos Alexandre; Franco, Douglas Wagner; Novaes, Fernando Valadares
2011-01-01

Resumo em inglês The concentration of 14 organic acids of 50 sugarcane spirits samples was determined by gas chromatography using flame ionization detection. The organic acids analytical quantitative profile in stills and column distilled spirits from wines obtained from the same must were compared. The comparison was also carried in "head", "heart" and "tail fractions of stills distilled spirits. The experimental data were analyzed by Principal Components Analysis (PCA) and pointed out t (mais) hat the distillation process (stills and column) strongly influences the lead spirits' organic acid composition and that producers' operational "cuts off" to produce "tail", "heart" and "head", fractions should be optimized.

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Ácidos graxos como marcadores biológicos da ingestão de gorduras/ Fatty acids as biological markers of fat intake

Vaz, Juliana dos Santos; Deboni, Fabíola; Azevedo, Mirela Jobim de; Gross, Jorge Luiz; Zelmanovitz, Themis
2006-08-01

Resumo em português Os ácidos graxos da dieta têm sido associados ao desenvolvimento de doenças crônicas. Os inquéritos alimentares, utilizados em estudos clínicos e epidemiológicos para estimativa da ingestão de nutrientes, apresentam limitações na coleta de informações. Nesse sentido, a utilização da composição de ácidos graxos do plasma e do tecido adiposo como marcadores do tipo de gordura alimentar pode fornecer uma medida mais acurada da ingestão de gorduras. Esta pes (mais) quisa tem como objetivo evidenciar aspectos metabólicos de alguns ácidos graxos e o papel como marcadores da ingestão de gorduras, e apresentar as técnicas analíticas empregadas na sua determinação. A biópsia do tecido adiposo, com determinação da composição de ácidos graxos, fornece uma informação a longo prazo da ingestão de gorduras, enquanto que a avaliação da composição das frações lipídicas séricas representa a ingestão a curto e médio prazos. Os ácidos graxos essenciais, os ácidos graxos saturados com número ímpar de carbonos (15:0 e 17:0) e os ácidos graxos trans, por não apresentarem síntese endógena, são utilizados como marcadores biológicos da ingestão de gorduras ou de sua própria ingestão. As principais técnicas utilizadas para a determinação de ácidos graxos são a cromatografia gasosa e a cromatografia líquida de alta precisão. No presente momento, o uso de marcadores biológicos para a ingestão de gorduras, associados aos inquéritos alimentares, representa a forma mais completa de avaliação da ingestão de gorduras. Resumo em inglês Dietary fatty acids have been associated with the development of chronic diseases. The methods commonly used in dietary assessment for estimating nutrient intake in clinical and epidemiological studies present limitations regarding data collection. The use of plasma and adipose tissue fatty acid composition as markers of the type of fat ingested has been studied and can provide a more accurate measurement of dietary fat intake. The aim of this study is to evidence the met (mais) abolic aspects of some fatty acids and their role as markers of dietary fat intake, and to present the analytical methods used in their determination. Analysis of the fatty acid composition of adipose tissue provides long-term information on dietary fat intake, whereas the determination of the fatty acid composition of serum lipid fractions accounts for the short- and medium-term dietary intakes. The essential fatty acids, the saturated fatty acids with an odd number of carbon atoms (15:0 and 17:0) and the trans fatty acids are used as biological markers of dietary fat intake or of these individual components, since they are not synthesized endogenously. Gas chromatography and high-performance liquid chromatography are the main analytical methods used to determine fatty acid composition. At present, the most comprehensive evaluation of dietary fat intake comprises the determination of biological markers in association with dietary assessment methods.

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Volatile compounds in the thermoplastic extrusion of bovine rumen

Silva, Ana Carolina Conti e; Bastos, Deborah Helena Markowicz; Arêas, José Alfredo Gomes; Facanali, Roselaine; Marques, Marcia Ortiz M.
2008-01-01

Resumo em inglês The volatile compounds of raw and extruded bovine rumen, extracted by dynamic headspace, were separated by gas chromatography and analyzed by GC-MS. Raw and extruded materials presented thirty-two volatile compounds. The following compounds were identified in raw bovine rumen: heptane, 1-heptene, 4-methyl-2-pentanone, toluene, hexanal, ethyl butyrate, o-xylene, m-xylene, p-xylene, heptanal, limonene, nonanal, dodecane, tridecane, tetradecane, pentadecane, hexadecane, hept (mais) adecane and octadecane. The following compounds were identified in the extruded material: 1-heptene, 2,4-dimethylhexane, toluene, limonene, undecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane and nonadecane. Mass spectra of some unidentified compounds indicated the presence of hydrocarbons with branched chains or cyclic structure.

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Variação da quantidade de β-cariofileno em óleo essencial de Plectranthus amboinicus (Lour.) Spreng., Lamiaceae, sob diferentes condições de cultivo/ Variation in the amount of β-caryophyllene in essential oil of Plectranthus amboinicus (Lour.) Spreng. Lamiaceae under different conditions of cultivation

Carneiro, Fabíola B.; D. Júnior, Irinaldo; Lopes, Pablo Q.; Macêdo, Rui O.
2010-09-01

Resumo em português O presente trabalho teve como objetivo avaliar a influência do adubo, da irrigação, da incidência solar, do horário de coleta e da idade da planta na quantidade de β-cariofileno no óleo essencial de Plectranthus amboinicus (Lour.) Spreng., Lamiaceae. As plantas foram cultivadas em canteiros experimentais entre os meses de dezembro de 2006 a setembro de 2007. O substrato utilizado foi adubo orgânico (esterco bovino), adubo mineral 1 [NPK (nitrogênio, fósforo (mais) e potássio)] e adubo mineral 2 (NPK com calcário) sob diferentes tratamentos. A técnica analítica quantitativa utilizada foi a cromatografia gasosa (GC/FID). De acordo com os resultados obtidos nos meses de menor precipitação de chuvas obteve-se maior rendimento de óleo essencial, e os meses de maior precipitação de chuvas mostraram uma tendência de baixos rendimentos. Resumo em inglês This study aimed to evaluate the influence of fertilizer, irrigation, the incidence sun, the time of collection and the plant in the amount of β-caryophyllene in the essential oil of Plectranthus amboinicus (Lour.) Spreng., Lamiaceae. The plants were grown in experimental beds between the months of December 2006 to September 2007. The substrate was used organic fertilizer (esterco veal), fertilizer mineral 1 [NPK (nitrogen, phosphorus and potassium)] and fertilizer m (mais) ineral 2 (NPK with limestone) under different treatments. The quantitative analytical technique was used to gas chromatography (GC/FID). According to the results obtained in months of lower precipitation of rainfall received are higher yield of essential oil, and the months of highest precipitation of rain showed a trend of low income.

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Utilização do índice de retenção linear para caracterização de compostos voláteis em café solúvel utilizando GC-MS e coluna HP-Innowax/ Linear retention index for characterization of volatile compounds in soluble coffee using GC-MS and HP-Innowax column

Viegas, Marcelo Caldeira; Bassoli, Denisley Gentil
2007-01-01

Resumo em inglês Gas chromatography coupled with mass spectrometry (GC-MS) is widely used for the characterization of volatile compounds. However, due to the complexity of the soluble coffee matrix, a complete identification of the components should not be based on mass spectra interpretation only. The linear index of retention (LRI) is frequently used to give support to mass spectra. The aim of this work is to investigate the characterization of the volatile compounds in soluble coffee s (mais) amples by GC-MS using LRI values found with a HP-INNOWAX column. The method used allows a significant increase of the reliability of identifying compounds.

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Utilização de subprodutos da indústria de biodiesel na alimentação de ruminantes

Abdalla, Adibe Luiz; Silva Filho, José Cleto da; Godoi, Antonio Roberto de; Carmo, Carolina de Almeida; Eduardo, José Luiz de Paula
2008-07-01

Resumo em português Com a introdução de óleo vegetal na cadeia produtiva do biocombustível no Brasil, é esperado o aumento da demanda por plantas oleaginosas e oferta de fibras vegetais resultantes da extração do óleo. Considerando a alimentação animal como elo entre a produção de biodiesel e a pecuária, propomos o estudo da utilização de subprodutos destes empreendimentos na alimentação visando aumentar a produtividade e diminuir a emissão de gases de efeito estufa pelos a (mais) nimais, gerando créditos de carbono e atendendo ao interesse da iniciativa privada. A técnica de produção de gases in vitro tem sido utilizada no LANA-CENA/USP com a finalidade de estudar o efeito de alimentos que possuem metabólitos secundários bioativos, na fermentação ruminal e degradabilidade da matéria orgânica (MOVD), bem como, no estudo da produção de metano. Resultados recentes mostraram que a substituição total do farelo de soja por tortas de algodão, dendê, mamona e pinhão manso proporcionou menor produção total de gases; e que a produção de metano foi significativamente afetada pela inclusão das tortas, sendo que o farelo de soja apresentou produção de metano de 15,3 mL/g MOVD. Diversos trabalhos mostram que as tortas e farelos apresentam características nutricionais adequadas para inclusão na dieta de ruminantes, entretanto, estudos criteriosos desses materiais enquanto matérias-primas para ração animal são necessários para avaliar possíveis efeitos deletérios devido à presença de metabólitos bioativos. Através de análises de cromatografia de alta resolução, podem ser identificadas essas substâncias que, em condições tropicais podem não apresentar a mesma toxicidade. A introdução de tortas com elevado teor de gordura nas dietas de ruminantes pode auxiliar na mitigação de metano entérico, e a produção de algumas oleaginosas pode contribuir com o seqüestro de carbono pelos solos de Cerrado na recuperação de pastagens, reduzindo a necessidade de desmatamentos. Resumo em inglês With the introduction of vegetable oil in the bio-fuel productive chain in Brazil, the increase in the demand of oleaginous plants is expected as well as the offer of the resulting vegetable fibers from the extraction of the oil. Considering the animal feeding as link between the biodiesel production and the livestock, we propose the study of the use of by-products of these enterprises in the feeding system seeking to increase the productivity and to reduce the emission o (mais) f greenhouse gases from the animals, generating carbon credits and assisting to the interest of the private initiative. The in vitro gas technique has been used at LANA-CENA/USP with the purpose of studying the effect of feeds containing secondary bioactive metabolites upon the ruminal fermentation and organic matter degradability (MOVD), as well as, in the study of methane production. The total substitution of the soybean meal for meals of cotton seed, palm oil, castor oil plant and jatropha provided less total gas production and the production of methane was affected significantly by the inclusion of the meals, with soybean meal presenting methane production of 15.3 mL/g MOVD. Literature data also show that meals from biodiesel production present appropriate nutritional characteristics for inclusion in the diet of ruminant, however, discerning studies of those materials while raw materials for animal ration are necessary to evaluate possible harmful effects due to the presence of bioactive metabolites. Through analyses of high resolution chromatography, those metabolites may be identified. The introduction of meals with high fat content in the diets of ruminant can aid in the mitigation of enteric methane, and the production of some oleaginous plants can contribute with the sequestering of carbon for the Cerrado soils in the recovery of pastures, reducing the need of deforestations

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Teores de compostos orgânicos em cachaças produzidas na região norte fluminense - Rio de Janeiro/ Organic compounds contents in cachaças produced in the northern Rio de Janeiro State - RJ

Souza, Leandro Marelli de; Ferreira, Karla Silva; Passoni, Luís César; Bevitori, Alice Barreto; Melo, Karen Vieira; Viana, Arivaldo Ribeiro
2009-01-01

Resumo em inglês This work aimed to quantify some organic compounds in "cachaças" (sugar cane spirit). The ethyl alcohol was quantified by densimetry, after distillation. The acetic acid, methyl alcohol, n-propyl alcohol, n-butyl alcohol, isobutyl alcohol, isoamyl alcohol (mixture of 2-methyl-butyl and 3-methyl-butyl), ethyl acetate and acetaldehyde were determined by gas chromatography; and the furfural, 5-hydroxy-methylfurfural and acrolein by high efficiency liquid chromatography. Fro (mais) m the 30 samples analyzed, 63.3% showed non-conformity with national legislation regarding at least one of the analyzed components.

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Selected nutrients in portuguese wild mushrooms analysed by gas chromatography and high performance liquid chromatography

Heleno, Sandrina A.; Barros, Lillian; Sousa, Maria João; Martins, Anabela; Ferreira, Isabel C.F.R.

DRIVER (Portuguese)

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Revegetação de cava de extração de argila com Acacia mangium: II - caracterização química da humina/ Revegetation of clay extraction sites with Acacia mangium: II - chemical aspects of humins

Schiavo, Jolimar Antonio; Canellas, Luciano Pasqualoto; Martins, Marco Antonio; Matos, Carlos Roberto Ribeiro
2007-10-01

Resumo em português Este trabalho foi realizado com o objetivo de caracterizar a natureza química dos compostos da humina extraída em solo de área degradada pela extração de argila, com vegetação espontânea de Brachiaria mutica (Forsk.) Stapf e revegetada com Acacia mangium Willd. Após extração e purificação, a humina foi submetida à transesterificação com metanol trifluorato de B (BF3-MeOH), obtendo-se as subfrações alifáticas e aromáticas. Essas subfrações foram subme (mais) tidas à cromatografia gasosa (Shimadzu GC-17A) combinada com a espectrometria de massa (Shimadzu GC/MS-qp5050A). Na subfração alifática obtida da cobertura com A. mangium, os compostos identificados foram: hexadecanoato de metila, octadecanoato de metila, heptadecano e 2-hidroxidodecanoato de metila; já na área com B. mutica os compostos foram: 14-metilpentadecanoato de metila e nonadecanoato de metila. Na subfração aromática, os compostos identificados na cobertura com A. mangium foram os mesmos obtidos naquela com B. mutica, sendo eles: 14-metilpentadecanoato de metila, 1,2 benzenodioato de 2 etilexila e butila. A leguminosa arbórea A. mangium proporcionou mudanças na fração mais recalcitrante das substâncias húmicas (humina), extraída da cava de extração de argila, preservando maior diversidade de compostos alifáticos. Resumo em inglês This study aimed at characterizing the chemical aspects of the humin compounds of a degraded clay extraction area covered with spontaneous vegetation of Brachiaria mutica (Forsk) Stapf or afforested with Acacia mangium Willd. After extraction and purification, humin was subjected to transesterification using BF3-MeOH (boron trifluorate methanol) to obtain the aliphatic and aromatic sub-fractions. These sub-fractions were analyzed by gas chromatography-mass spectrometry. T (mais) he following compounds were identified in the aliphatic sub-fraction of the A. mangium site: methyl hexadecanoate, methyl octadecanoate, methyl 2-hydroxidodecanoate and heptadecano, on the other hand, in B. mutica site the compounds were: methyl 14-methylpentadecanoate and methyl nonadecanoate. In the aromatic sub-fractions the compounds identified in soil samples colleted in A. mangium site were the same as those identified in B. mutica: methyl 14-methylpentadecanoate, 2-ethylexila 1.2 benzenodioate and buthyl. The re-vegetation of degraded area with the leguminous tree A. mangium inmduced changes in the recalcitrant fraction of humic substances (humin), preserving the diversity of the aliphatic compounds.

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Quantificação do linalol no óleo essencial da Aniba duckei Korstermans utilizando uma nova coluna capilar POLYH4-MD em Cromatografia Gasosa/ Quantitation of linalol in the essential oil of Aniba duckei Korstermans using a new POLYH4-MD capillary column in Gas Chromatography

Silva, Denise Domingos da; Chierice, Gilberto Orivaldo; Galhiane, Mário Sérgio; Chaar, Jamal da Silva; Mouchrek-Filho, Victor Elias
2003-08-01

Resumo em inglês In the present work a polyurethane polymer derived from castor oil was used as stationary phase for capillary gas chromatography. The polymer was obtained by reaction of hydroxylated compound and isocynate (NCO), forming urethane. Columns of 7 m x 0,25 mm were then coated with this stationary phase (film thickness of 0,25 µm) using static coating method. The Grob test was also performed. Samples of essential oil of the Aniba duckei Korstermans was then analysed in POLYH4 (mais) -MD capillary column in order to evaluate its chromatographic perfomance. The linalool was found to be the major component and has been used as compound of departure for many important syntheses. Results show that the experimental columns give higher resolution and can be employed for analysis of essentials oils.

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Perfil nutricional de alimentos com alegação de zero gordura trans/ Nutritional profile of foods with zero trans fatty acids claim

Gagliardi, Ana Carolina Moron; Mancini Filho, Jorge; Santos, Raul D.
2009-01-01

Resumo em português OBJETIVO: Avaliar a composição de ácidos graxos de alguns alimentos industrializados disponíveis no mercado brasileiro nos quais houve redução da quantidade de ácidos graxos trans. Verificar também se estes alimentos atendem às quantidades recomendadas de consumo de gordura saturada, após redução de gordura trans. MÉTODOS: Alimentos industrializados (margarina cremosa A e B, margarina com fitosterol, biscoito doce recheado, biscoito salgado sem recheio, batat (mais) a frita e lanche com hambúrguer de fast food multinacional com alegação de 0% de gordura trans foram adquiridos em pontos comerciais e analisados em cromatógrafo gasoso. RESULTADOS: Apesar da redução nas quantidades de ácidos graxos trans, os alimentos analisados contêm grandes quantidades de gorduras saturadas principalmente o ácido palmítico. Além disso, alguns dos alimentos estudados apresentam uma razão n-3/n-6 fora do recomendado para a prevenção da aterosclerose. CONCLUSÃO: O consumo irrestrito desses alimentos tem forte potencial deletério para a saúde. O rótulo de ausência de ácidos graxos trans deve ser visto com cuidado e não significa uma liberação para o consumo irrestrito desses alimentos. Resumo em inglês OBJECTIVE: To evaluate the composition of fatty acids in some foods available in the Brazilian market in which there was a claimed reduction in the amount of trans fatty acids. Also evaluate whether these foods meet recommended amounts for saturated fat consumption, after reduction of trans fat amounts. METHODS: Industrialized food (creamy margarine A and B, plant sterol margarine, stuffed sweet biscuit, salty biscuit without stuffing, French fried potatoes and a burger l (mais) unch from a multinational chain of "fast food" all with the allegation of 0% trans fat content were purchased in commercial points and analyzed by gas chromatography. RESULTS: Despite the reduction in trans fatty acid amounts, analyzed foods contained large concentrations of saturated fats mainly palmitic acid. Moreover, some of the foods studied showed a n-6/n-3 ratio outside the recommended for atherosclerosis prevention. CONCLUSION: The unrestricted consumption of such foods has strong deleterious health potential. The absence of trans fatty acid label should be viewed with caution and does not mean a release for unrestricted consumption of such foods.

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Perfil de colesterol de ovos comerciais e ovos enriquecidos com ácidos graxos polinsaturados ômega-3/ Profile of cholesterol in regular commercial eggs and omega-3 polyunsaturated fatty acids enriched eggs

Mourthé, K.; Martins, R.T.
2002-08-01

Resumo em português Determinou-se quantitativamente, por cromatografia gasosa, o teor colesterol de ovos enriquecidos com ácidos graxos polinsaturados ômega-3 e de ovos comuns disponíveis no mercado de Belo Horizonte/MG. Foram analisadas duas marcas de ovos comuns e duas de ovos enriquecidos com cinco repetições por amostragem. Não houve diferença entre os níveis de colesterol para os tipos de ovos estudados. Resumo em inglês Two kinds of table eggs, normal and omega-3 enriched, available in the commerce of Belo Horizonte, Brazil, were analyzed by gas chromatography. The cholesterol contents were not different (P>0.05) between the two egg types.

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Otimização de metodologia para derivação de desoxinivalenol através de planejamento experimental/ Optimization of the methodology for deoxynivalenol derivatization by experimental planning

Garda, Jaqueline; Badiale-Furlong, Eliana
2008-01-01

Resumo em inglês The objective of this work was to optimize the derivatization reaction for determining deoxynivalenol (DON) by gas chromatography employing an experimental planning procedure. The factors were: temperature, reaction time, catalyst and trifluoroacetic anhydride concentration. The relative peak areas were used to evaluated the effects. The best conditions for DON derivatization were 200 µL TFAA and 18 mg sodium bicarbonate for 6 min at 74 ºC for 7 to 21 µg of DON. Under these conditions, the detection limit was 1.4 µg of DON.

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Métodos para avaliação das emissões de gases do efeito estufa no sistema solo-atmosfera/ Methods for the assessment of greenhouse gases emissions in the soil-atmosphere system

Costa, Falberni de Souza; Gomes, Juliana; Bayer, Cimélio; Mielniczuk, João
2006-04-01

Resumo em português A escolha do método para avaliar as emissões de gases do efeito estufa (GEE) é uma etapa importante para o conhecimento e/ou desenvolvimento de práticas agrícolas com potencial de mitigação do aquecimento global. A presente revisão tem por objetivo apresentar vantagens e limitações de métodos utilizados para quantificação dos fluxos de dióxido de carbono (CO2), metano (CH4) e óxido nitroso (N2O) no sistema solo-atmosfera. O balanço dos estoques de C orgân (mais) ico no solo em sistemas conservacionistas de manejo permite avaliar o influxo líquido anual de C-CO2 atmosférico no solo em comparação a sistemas de manejo convencional. Maior sensibilidade na determinação direta das emissões de CO2 in situ pode ser obtida pelo uso de câmaras sobre o solo. Nesse caso, podem ser determinadas taxas diárias com o método da captura do CO2 em solução alcalina e quantificação por titulação, e taxas horárias com o uso de analisadores automáticos de infravermelho ou cromatógrafos a gás. Pelo uso de cromatografia, é possível também a avaliação das emissões de N2O e CH4 os quais apresentam, respectivamente, potencial de aquecimento global 296 e 23 vezes superior ao do CO2. A análise dos três GEE é necessária quando se objetiva avaliar o potencial de um dado sistema de manejo na mitigação do aquecimento global, o qual pode ser expresso em C equivalente. Resumo em inglês The sellection of the method for evaluating greenhouse gases (GHG) emissions is an important step in studies aiming at the development of agricultural practices with potential to mitigate the global warming. The objective of this review was to present advantages and disvantages of available methods to quantify fluxes of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) in the soil-atmosphere system. Carbon sequestration or annual net influx rates of C-CO2 in con (mais) servation tillage systems can be evaluated through the soil carbon budget. In situ evaluations can be carried out with closed chambers, where alkaline traps are used to determination of daily influxes of CO2 while gas chromatography and automatic infrared gas analyzers permit to estimate horary fluxes. In addition to CO2, gas chromatography is able to measure N2O and CH4 emissions, gases that have a global warming potential 296 and 23 times higher than CO2, respectively. Measurement of the three GHG emissions permit to estimate the net effect of soil management systems on atmosphere rodiative forcing in equivalent C.

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Métodos para análise de ácido clorogênico/ Analytical methods for chlorogenic acid

De Maria, Carlos Alberto Bastos; Moreira, Ricardo Felipe Alves
2004-08-01

Resumo em inglês This paper describes the analytical methods for determination of total chlorogenic acid (CGA) and their individual isomers. Spectrofotometric methods are adequate for total CGA analysis in green coffee but they can provide inflated results for coffee products. High pressure liquid chromatography (HPLC) with gel permeation column and ultraviolet (UV) monitoring is adequate for the simultaneous analysis of total CGA, alkaloids and sugars in coffee products. HPLC-UV-reversed (mais) phase is a simple, rapid and precise method for the determination of the individual isomers of CGA. Gas chromatography (GC) also is applied to the analysis of the individual isomers but phenolic acids need to be derivatized before analysis. Both HPLC- and GC-mass spectrometry provide an unequivocal identification of the individual isomers. The capillary electrophoresis method is simple, rapid and adequate to the simultaneous analysis of polyphenols and xanthines. Advantages and limitations of each method are discussed throughout the text.

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Métodos de amostragem e análise para compostos reduzidos de enxofre atmosférico/ Sampling and analytical methods for atmospheric reduced sulphur compounds

Cruz, Lícia P. S.; Campos, Vânia P.
2008-01-01

Resumo em inglês This work presents a review of sampling and analytical methods that can be applied to atmospheric traces of reduced sulphur compounds (RSC) in the atmosphere. Sampling methodology involving discontinuous methods with preconcentration is mostly used. For the most part, adsorption on solids and cryogenic capture are applied as a procedure. The analysis of these compounds has been done mainly by gas chromatography with FPD, fluorescence and spectrophotometry. Advantages and (mais) disadvantages of the methodologies are also mentioned in this paper, aiming to guide the reader towards the most appropriate choice of a sampling and analytical method for RSCs.

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Metodologias analíticas para determinação das fumonisinas em milho e alimentos à base de milho/ Analitycal metodologies for the determination of fumonisins in maize and maize-based food products

Lino, Celeste M.; Silva, Liliana J. G.; Pena, Angelina S.
2006-04-01

Resumo em inglês Fumonisins are mycotoxins occurring worldwide, mainly in maize and maize-based food products, which could affect animal and human health. This paper reviews analytical methodologies for the determination of these fungal toxins in foods. It includes extraction, cleanup, derivatization procedures, detection, quantification, and confirmation procedures. Initial attempts at gas chromatographic methods and thin layer chromatography were supplanted by liquid chromatographic met (mais) hods, mainly performed with fluorometric detection, or mass spectrometry detection, enabling the analysis of polar and thermolabile chemicals without chemical derivatization, which results in lower limits of detection. Alternative methods, such as enzyme linked immunosorbent assay or zone capillary zone electrophoresis, are also described.

Scientific Electronic Library Online (Portuguese)

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Lipídios em sedimentos arqueológicos: resultados preliminares do sítio arqueológico Rio do Meio, Ilha de Santa Catarina (SC)/ Lipids in archaeological sediments: preliminary results of the archaeological site Rio do Meio, Santa Catarina Island (SC), Brazil

Hansel, Fabrício Augusto; Fossari, Teresa Domitila; Madureira, Luiz Augusto dos Santos
2008-02-01

Resumo em português Este trabalho foi realizado com o objetivo de avaliar a distribuição de lipídios em sedimentos arqueológicos do sítio Rio do Meio, Ilha de Santa Catarina. Nos extratos totais de lipídios, analisados por cromatografia gasosa e espectrometria de massas (CG e CG-EM), predominaram os compostos ácidos e álcoois saturados. Foram detectados pelo menos dois tipos de matéria orgânica: uma antiga e outra comparativamente recente. Na primeira, o extrato total de lipídios (mais) foi dominado por ácidos graxos de cadeias curtas ( Ac20:0 e Al20:0). Em contraste, na deposição classificada como recente, foram identificados em maiores teores os ácidos e álcoois de cadeias longas (> Ac20:0 e Al20:0). Neste estudo, foi possível observar a incorporação de material orgânico procedente de fontes de origem vegetal, bacteriana e, possivelmente, animal (gorduras) nos sedimentos arqueológicos analisados. Resumo em inglês In this study the distribution of lipid compounds was evaluated in sediment samples of an archaeological site Rio do Meio, Santa Catarina Island, Brazil. In the total lipid extracts, analyzed by gas chromatography and mass spectrometry (GC and GC-MS), saturated fatty acids and alcohols were predominant. At least two sources of organic matter were detected, an older and a more recent one. In the old deposit, the most abundant lipids were short-chain fatty acids ((mais) followed by a minor composition of long-chain fatty acids and alcohols (> Ac20:0 and Al20:0). In contrast, the fresh deposit was dominated by long-chain fatty acids and alcohols (> Ac20:0 and Al20:0). This paper described the incorporation of vegetal, bacterial and possible animal (fat) sources into the archaeological sediments analyzed.

Scientific Electronic Library Online (Portuguese)

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Lipophilic and hydrophilic antioxidants, lipid peroxidation inhibition and radical scavenging activity of two Lamiaceae food plants

Fernandes, Ângela S.F.; Barros, Lillian; Carvalho, Ana Maria; Ferreira, Isabel C.F.R.

Medicinal and aromatic plants are highly prized all over the world. According to local cuisine and pharmacopoeias, they used to be important as dietary supplements, providing bioactive compounds. Herein, we describe lipophilic (fatty acids, tocopherols and carotenoids) and hydrophilic (ascorbic acid...

DRIVER (Portuguese)

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Investigation of the occurrence of pesticide residues in rural wells and surface water following application to tobacco

Bortoluzzi, Edson C.; Rheinheimer, Danilo S.; Gonçalves, Celso S.; Pellegrini, João B. R.; Maroneze, Aline M.; Kurz, Márcia H. S.; Bacar, Nádia M.; Zanella, Renato
2007-01-01

Resumo em inglês In this work the exposure of wells and surface water to pesticides, commonly used for tobacco cropping, was assessed. Water consumption wells and surface water flows were sampled at different times. After a preconcentration step with solid phase extraction (SPE), the selected pesticides were determined by gas chromatography with electron capture detection (GC-ECD) or high performance liquid chromatography with diode array detection (HPLC-DAD). No pesticides were detected (mais) in the well water samples and surface water flow in the winter season. However, in the spring and summer higher concentrations of chlorpyrifos and imidacloprid were found in the water source samples. Atrazine, simazine and clomazone were also found. The occurrence of pesticides in collected water samples was related with the application to tobacco.

Scientific Electronic Library Online (Portuguese)

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Intoxicação por organofosforado em bovinos no Rio Grande do Sul/ Poisoning by organophosphate in cattle in southern Brazil

Oliveira-Filho, José C; Carmo, Priscila M.S; Pierezan, Felipe; Tochetto, Camila; Lucena, Ricardo B; Rissi, Daniel R; Barros, Claudio S.L
2010-10-01

Resumo em português Descreve-se um surto de intoxicação por organofosforado (ORF) em bovinos na mesorregião centro ocidental do Rio Grande do Sul. A água fornecida a 49 bovinos foi contaminada com ORF e carbamato (CM). Vinte bovinos morreram após quadro clínico de poucas horas. Foram observados os clássicos sinais clínicos de hiperestimulação do sistema parassimpático incluindo incoordenação motora, agressividade, sialorreia, tremores musculares e, em alguns casos, diarreia. Na (mais) necropsia e histopatologia não foram observadas alterações morfológicas significativas. ORF e CM foram detectados por cromatografia em camada delgada em amostras de tecido de dois bovinos afetados. Adicionalmente, uma amostra da água consumida pelos bovinos foi positiva para ORF e CM e outras duas foram positivas para ORF. Uma análise quantitativa realizada por cromatografia gasosa no conteúdo do abomaso de um bovino afetado, revelou 0,93µg/g de mancozebe (CM) e 0,07 µg/g de forato (ORF). Resumo em inglês An outbreak of organophosphate (ORF) poisoning in cattle occurred in the central-midwestern region of Rio Grande do Sul, Brazil. The water available for 49 cattle was contaminated with ORF and carbamate (CM). Twenty cows died after a clinical course that lasted for few hours. The classical clinical signs of over stimulation of the parasympathetic nervous system were observed, including motor incoordination, aggressiveness, drooling, muscle tremors and, on occasion, diarrh (mais) ea. Significant morphological changes were not observed at necropsy or at histopathological examination. ORF e CM were detected by thin layer chromatography in tissue samples of two affected cattle and in a sample from the water consumed by the affected cattle. Additionally, two other water samples accessed by the affected cattle were positive for ORF. A quantitative analysis carried out by gas chromatography in the abomasum contents of an affected cow revealed 0.93µg/g of mancozebe (CM) and 0.07µg/g of phorate (ORF).

Scientific Electronic Library Online (Portuguese)

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Influência do processamento pós-colheita e armazenamento na composição química da droga vegetal e do óleo essencial de carqueja [Baccharis trimera (Less.) DC.]/ Influence of post-harvest processing and storage on the chemical composition of drug and essential oil from "carqueja" [Baccharis trimera (Less.) DC.]

Silva, F.G.; Nascimento, V.E.; Pinto, J.E.B.P.; Oliveira, C.B.A.; Santos, M.R.; Ferri, P.H.
2010-12-01

Resumo em português A carqueja-amarga [Baccharis trimera (Asteraceae)] é uma espécie originária do centro-sul da América do Sul. Análises qualitativas e quantitativas foram realizadas utilizando-se a técnica de CG-MS, para avaliar o efeito de diferentes formas de beneficiamento pós-colheita de drogas vegetais constituídas de partes aéreas de carqueja na composição química do óleo essencial, bem como verificar variações na composição quando conservado a -6ºC, durante 8 meses (mais) . O armazenamento da droga pulverizada reduziu significativamente o teor de óleo essencial, o que não aconteceu na droga fragmentada. Os teores dos constituintes majoritários espatulenol e ledol não foram influenciados pelo tratamento pós-colheita, embora tenham apresentado variações distintas redução nas concentrações de ledol e aumento nos teores de espatulenol. Verificou-se que as drogas fragmentadas podem ser armazenadas por até 12 meses e pulverizadas no momento da extração, não conferindo redução no teor de óleo essencial, nem dos constituintes químicos. O armazenamento a -6ºC por até oito meses, provocou variações quantitativas em alguns constituintes minoritários, tais como a-guaieno, b-selineno, germacreno B e espatulenol. Resumo em inglês "Carqueja-amarga" [Baccharis trimera (Asteraceae)] is a species from the central south of South America. Qualitative and quantitative analyses were performed using the technique gas chromatography coupled to mass spectrometry to evaluate the effect of different post-harvest processing forms of drugs constituted of parts of "carqueja" on the chemical composition of its essential oil. The variation in the chemical composition of the essential oil stored at -6ºC for up to e (mais) ight months was also evaluated. Storage of powdered drug significantly reduced the essential oil content, which was not observed for fragmented drug. The concentration of the major constituents of "carqueja" essential oil, spathulenol and ledol, was not affected by the post-harvest treatment, although they presented distinct variations, with ledol concentrations reducing and spathulenol concentrations increasing. We found that fragmented drugs can be stored for up to 12 months and powdered at the moment of extraction, without reducing the concentration of the essential oil or its chemical constituents. Storage at -6ºC for eight months caused quantitative variations in some minor constituents of the essential oil such as a-guaiene, b-selinene, germacrene B and espathulenol.

Scientific Electronic Library Online (Portuguese)

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Influência do material do destilador na composição química das aguardentes de cana: parte II/ Influence of the pot still material on the chemical composition of Brazilian sugar cane spirit: part II

Cardoso, Daniel R.; Lima-Neto, Benedito S.; Franco, Douglas W.; Nascimento, Ronaldo F. do
2003-03-01

Resumo em inglês The quantitative chemical analysis of the Brazilian sugar cane spirit distilled from glass column packaged with copper, stainless steel, aluminum sponge, or porcelain balls is described. The main chemical compounds determined by gas chromatography coupled with flame ionization (FID) and flame photometric (FPD) detectors and liquid chromatography coupled with diode array detector are aldehydes, ketones, carboxylic acids, alcohols, esters and dimethylsulfite (DMS). The spir (mais) its produced either in columns filled with copper or aluminum pot still exhibits the lowest DMS contents but the higher sulfate and methanol contents, whereas spirits produced in stainless steel or porcelain showed higher DMS concentration and lower teors of sulfate ion and methanol. These observations are coherent with DMS oxidation to sulfate, with methanol as by product, in the presence of either copper or aluminum.

Scientific Electronic Library Online (Portuguese)

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Influência do material do alambique na composição química das aguardentes de cana-de-açúcar/ The influence of the material used in building the distiller in the sugar-cane-spirit chemical profile

Nascimento, Ronaldo F.; Cardoso, Daniel R.; Lima Neto, Benedito dos Santos; Franco, Douglas Wagner; Farias, João Bosco
1998-11-01

Resumo em inglês This paper describes variations in the profile of the main volatile organic compounds present in Brazilian sugar cane spirits distilled in copper and stainless steel distillers. The main organic compounds: aldehydes, ketones, carboxylic acids, alcohols and esters, were determined through High Performance Liquid Chromatography (HPLC) and High Resolution Gas Cromatography (HRGC). The spirits produced in copper distillers exhibit higher contents of aldehydes with respect to (mais) the ones produced in stainless steel. The inverse is true with respect to the higher alcohol and ester contents. No significant variation has been observed for the carboxylic acids.

Scientific Electronic Library Online (Portuguese)

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Influência da ingestão de sardinha nos níveis de ácidos graxos poliinsaturados da série ômega3 no leite materno/ The influence of sardine consumption on the omega-3 fatty acid content of mature human milk

Patin, Rose V.; Vítolo, Márcia R.; Valverde, Mara A.; Carvalho, Patrícia O.; Pastore, Gláucia M.; Lopez, Fábio Ancona
2006-02-01

Resumo em português OBJETIVOS: A proposta deste trabalho foi verificar a influência da ingestão de sardinha, alimento rico em ácidos graxos poliinsaturados da série ômega3, na composição do leite materno. MÉTODOS: Estudo prospectivo avaliou 31 nutrizes acompanhadas no Hospital Guilherme Álvaro, as quais receberam 2 kg de sardinha fresca por duas vezes, em intervalos de 15 dias. Nos tempos 0, 15 e 30 dias, realizou-se inquérito alimentar de 24 horas e coleta de leite. Determinaram-s (mais) e os ácidos graxos do leite materno por cromatografia a gás. Para análise estatística dos resultados, utilizaram-se testes não paramétricos, com nível de significância p Resumo em inglês OBJECTIVES: The purpose of this study was to investigate what effect the intake of sardines, rich in omega-3 series polyunsaturated fatty acids, has on the composition of breastmilk. METHODS: This was a prospective study of 31 nursing mothers under observation at the Hospital Guilherme Álvaro. Each was given 2 kg of fresh sardines twice with a 15-day interval. Milk was sampled and a 24-hour dietary recall questionnaire was applied on days 0, 15 and 30. Milk was assayed f (mais) or fatty acid content by gas chromatography. Statistical analysis of the results was performed using nonparametric tests with significance set at p

Scientific Electronic Library Online (Portuguese)

42

Identificação dos principais componentes do fungicida guazatine através da cromatografia a gás e cromatografia a gás acoplada com espectrometria de massas/ Identification of the main components of guazatine fungicide by gas chromatography and gas chromatography-mass spectrometry

Arquimedes, Lavorenti; Hudson, Harry Robinson; Pianka, Max
1998-04-01

Resumo em inglês Hexafluoroacetylaceton derivatives of some synthesized components of the guazatine fungicide were prepared, and their separation and identification performed through gas chromatography and gas chromatography-mass spectrometry. The chromatogram obtained from hexafluoroacetylacetone derivative of the commercial guazatine presented 14 major peaks, and 9 of them were identified through both techniques mentioned above.

Scientific Electronic Library Online (Portuguese)

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Hidrólise do óleo de Azadirachta indica em água subcrítica e determinação da composição dos triacilglicerídeos e ácidos graxos por cromatografia gasosa de alta resolução a alta temperatura e cromatografia gasosa de alta resolução acoplada à espectrometria de massas/ Hydrolysis of Azadirachta indica oil using subcritical water and determination of triacylglycerides and fat acids by HT-HRGC-FID and HRGC-MS

Pinto, Jair Sebastião da Silva; Lanças, Fernando Mauro
2010-01-01

Resumo em inglês The development of modern analytical tools plays an important role in quality control. The main purpose of this study was to explore the use of subcritical water as a versatile analytical tool, employed simultaneously as a reagent and solvent, as well as the application of high temperature-high resolution gas chromatography (HT-HRGC) to develop a procedure for the analysis of triacylglycerides and fatty acids in Azadirachta indica A. Juss. (Neem) oil without the need for (mais) solvents, chemical reagents, or catalytic agents. The developed method presented satisfactory results and is in agreement with the concepts of Green Analytical Chemistry (GAC).

Scientific Electronic Library Online (Portuguese)

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Heterogeneidade de álcoois secundários em aguardentes brasileiras de diversas origens e processos de fabricação/ Heterogeneity of secondary alcohols in brazilian sugar cane spirits from diverse origins and processes of manufacture

Penteado, José Carlos Pires; Masini, Jorge Cesar
2009-01-01

Resumo em inglês Secondary alcohol concentrations in sugar cane spirits from different origins were determined by gas chromatography. A great variation in the concentration of the secondary alcohols was found in these spirits. Of the 33 brands analyzed, 8 of them were found to be out of conformity with the legislation. Sec butanol, for which the maximum allowed concentration level is 100 mg.L-1 in absolute ethanol, was found within a concentration range between 5 mg.L-1, the limit of quan (mais) titation (LQ) and 408 mg.L-1 in absolute ethanol. Sugar cane samples from Salinas, MG, were the only ones that exhibited self similarity because of the low concentrations of n-butanol and n-amylic alcohol (

Scientific Electronic Library Online (Portuguese)

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Fluidos supercríticos em química analítica. III.: aplicações/ Supercritical fluids in analytical chemistry. III.: applications

Carrilho, Emanuel; Tavares, Maria Cecília H.; Lanças, Fernando M.
2006-07-01

Resumo em inglês The first two papers in this series described the basic theory involved in supercritical fluid chromatography (SFC), how the technique evolved from gas and liquid chromatography and how the instrumentation was developed. Over the last two years, a commercial, dedicated packed-column SFC/MS instrument appeared on the market. The SFC continues to grow in use, with fundamental developments, coupled with a steady rise in the number of industrial users and applications.

Scientific Electronic Library Online (Portuguese)

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Fluidos supercríticos em química analítica. II. Cromatografia com fluido supercrítico: instrumentação/ Supercritical fluid in analytical chemistry. II. Supercritical fluid chromatography: instrumentation

Carrilho, Emanuel; Tavares, Maria Cecília H.; Lanças, Fernando M.
2003-10-01

Resumo em inglês The first paper in this series discussed the basic theory involved in supercritical fluid chromatography (SFC) and how the technique progressed from gas and liquid chromatography. The first SFC instruments were simple adaptations of the commercially available liquid chromatographs with packed columns followed by modifications in gas chromatographs using open tubular capillary columns. In this paper, the most important aspects regarding instrumentation are covered, including practical, simple, and the most important, inexpensive solutions to build a home-made SFC system.

Scientific Electronic Library Online (Portuguese)

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Extração e pré-concentração de compostos orgânicos voláteis por permeação em membrana para análise cromatográfica/ Extraction and pre-concentration of volatile organic compounds by membrane permeation for chromatography analysis

Rocha, Eduardo Carasek da; Valente, Antonio Luiz Pires; Augusto, Fabio
2000-02-01

Resumo em inglês This work discusses sample preparation processes for gas chromatography (GC) based on the technique of extraction through membrane permeation (MPE). The MPE technique may be easily coupled to GC via a relatively simple device, which is a module that holds the membrane and is directly connected to the GC column. The possibility of operational errors due to sample handling is substantially reduced in an MPE-GC system because the sample preparation and the chemical analysis (mais) are accomplished as a one-step process. The MPE technique is of relatively wide application as it can be used for aqueous samples, solid samples and gaseous samples. Depending on the type of sample the extraction is performed with the membrane in direct contact with the sample or in contact with its headspace. The MPE-GC technique is very useful in trace analysis, due to the time-dependent enrichment of the analyte. A typical application of MPE-GC is the analysis of VOCs present in water that may be accomplished with detection limits at the low ppb (mugL-1) level.

Scientific Electronic Library Online (Portuguese)

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Experimento didático sobre cromatografia gasosa: uma abordagem analítica e ambiental/ Didactic experiment on gas chromatography: an environmental and analytical approach

Penteado, José Carlos P.; Magalhães, Dulce; Masini, Jorge C.
2008-01-01

Resumo em inglês This paper describes an experiment to teach the principles of gas chromatography exploring the boiling points and polarities to explain the elution order of a series of alcohols, benzene and n-propanone, as well as to teach the response factor concept and the internal standard addition method. Retention times and response factors are used for qualitative identification and quantitative analysis of a hypothetical contamination source in a simulated water sample. The intern (mais) al standard n-propanol is further used for quantification of benzene and n-butanol in the water sample. This experiment has been taught in the instrumental analysis course offered to chemistry and oceanography students.

Scientific Electronic Library Online (Portuguese)

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Evaluation of paraffins biodegradation and biosurfactant production by Bacillus subtilis in the presence of crude oil/ Avaliação da biodegradação de parafinas e da produção de biosurfactante por Bacillus subtilis na presença de petróleo

Queiroga, Carmen Lucia; Nascimento, Lídia Regina; Serra, Gil Eduardo
2003-12-01

Resumo em português Os experimentos com Bacillus subtilis para avaliação da tensão superficial foram realizados com meio de cultivo contendo como nutrientes básicos 0,4% de ions nitrato e 4% de glicose, na presença de petróleo. A produção de surfactina foi observada pela redução da tensão superficial do meio de cultura fermentado. Surfactina foi isolada a partir do meio de cultura fermentado por B. subtilis, por precipitação ácida seguida de extração com clorofórmio-metanol. (mais) A avaliação da composição dos alcanos lineares (parafinas) foi realizada por cromatografia gasosa. Observamos uma significativa redução da tensão superficial do meio de cultura indicando que a produção de biosurfactante não foi inibida pela presença de parafina, e que as parafinas leves podem ter sido consumidas. Resumo em inglês Bacillus subtilis experiments for surface tension evaluation were accomplished with culture medium containing 0.4% nitrate ions and 4% glucose basic nutrient in the presence of crude oil. Surfactin production was observed by surface tension reduction of the culture broth. Surfactin was isolated from Bacillus subtilis fermented broth, by acid-precipitation followed by extraction with chloroform-methanol. Evaluation of the linear alkanes composition was performed by capilla (mais) ry gas chromatography. We observed a significant reduction of the surface tension of the fermented broth indicating that the biosurfactant production was not inhibited by the crude oil presence, and that the light paraffins might have been consumed.

Scientific Electronic Library Online (Portuguese)

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Estudo de compostos orgânicos em lixiviado de aterros sanitários por EFS e CG/EM/ Study of organic compounds in landfill leachate by SPE and GC/MSD

Nascimento Filho, Irajá do; von Mühlen, Carin; Caramão, Elina Bastos
2001-08-01

Resumo em inglês The main purpose of this work was the qualitative study of organic compounds in landfill leachate. The samples were collected from a sanitary landfill located at Gravataí, a southern Brazilian city, that receive both, industrial and domestic refuse. The samples were submitted to solid phase extraction (SPE) with XAD-4 resin as the stationary phase. The instrumental analysis was performed by Gas Chromatography with a Mass Spectrometry Detector (GC/MSD). The compounds achi (mais) eved in the SPE extracts were tentatively identified by the GC/MS library. It was found several oxygen and nitrogen compounds like carboxylic acids, ketones, amines and amides. Sulfur compounds and phthalate esters are also identified.

Scientific Electronic Library Online (Portuguese)

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Estudo da variação da concentração de metano no biogás produzido a partir das águas residuárias do café/ A study on the variation of methane concentration in biogas produced from coffee wastewater

Prado, Marco Antônio Calil; Campos, Cláudio Milton Montenegro; Silva, Julia Ferreira da
2010-04-01

Resumo em português A água residuária do café (ARC), originada no processamento dos frutos do cafeeiro, produz quantidade considerável de biogás que pode e deve ser utilizado como fonte de energia alternativa e complementar. Neste trabalho, foi estudada a variação da concentração de metano do biogás produzido a partir das ARC, por tratamento anaeróbio, em reator UASB, em escala laboratorial. As amostras foram coletadas durante 86 dias. As análises da concentração de metano fora (mais) m realizadas por cromatografia gás-sólido (CGS). A produção de biogás e de metano, foi de 0,545 a 0,602 m³ kg-1DQO removida e de 0,382 a 0,421 m³ kg-1 DQO removida, respectivamente. Os resultados da concentração de metano no biogás variaram de 48,60 a 68,14 %, influenciados pela variação dos parâmetros temperatura, pH, acidez e compostos fenólicos presentes nas ARC. Como havia sido previsto, as maiores concentrações de metano foram verificadas nos períodos em que o pH estava mais próximo da neutralidade. Resumo em inglês The wastewater produced from wet coffee processing (WCP), originated from the coffee fruits, can produce great quantities of biogas, which, in turn, can be also used as an alternative or complementary energy source. In this research, we studied the variation of methane concentration produced by WCP in a laboratory-scale UASB reactor with anaerobic treatment. The samples were collected during a period of 86 days. The methane concentration was measured through gas solid chr (mais) omatography (GSC). The production of biogas and methane ranged from 0.545 to 0.602 m³ kg-1DQO removed and from 0.382 a 0.421 m³ kg-1 DQO removed, respectively. Methane presence in the biogas ranged from 48.60% to 68.14 %. This variation was influenced by the following parameters: temperature, pH, acidity, and phenol compounds present in the WCP. As expected, greater concentrations of methane gas were verified during the periods when the pH close to neutral.

Scientific Electronic Library Online (Portuguese)

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Estudo da adsorção/dessorção do ácido 2,4 diclorofenoxiacético (2,4d) em solo na ausência e presença de matéria orgânica/ Study of adsorption/desorption of herbicide 2,4D in soil

Vieira, Eny Maria; Prado, Alexandre Gustavo Soares do; Landgraf, Maria Diva; Rezende, Maria Olímpia de Oliveira
1999-06-01

Resumo em inglês The herbicides are being used in huge quantities for various porpouses. Once the herbicide finds its way into the environment, a major part of it comes in contact with soil. Humic substances are major organic constituents of soil. These substances may interact with herbicides in different modes and adsorption is probably the most important one. Adsorption will control the quantity of herbicide in the soil solution, and determines its persistence, leaching, mobility and bi (mais) oavailability. In this work we studied the interaction between the herbicide 2,4D and soil in the presence and absence of organic matter. The methodology utilized for the determination of 2,4D was gas chromatography with eletron capture detector. The behavior of 2,4D was evaluated through Freundlich isotherms. It was verified that the herbicide 2,4D has a large adsorption in the humic acid .

Scientific Electronic Library Online (Portuguese)

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Estudo da Determinação dos Grupos Silanóis ( º Si-OH) em Sílica: Aplicação à Materiais de Recheio Utilizados em Cromatografia Gasosa/ Silanols determination study in silica: application to packings used in gas chromatography

Pizzutti, Ionara Regina; Schwerz, Letícia; Viaro, Nádia Suzana Schneider; Adaime, Martha Bohrer
1997-06-01

Resumo em inglês A simple chemical method has been developed to quantify the silanol groups (º Si-OH) in silica as well as in coated chromatographic supports for use in packed - column Gas Chromatography. After adsorption of 10 mg/mL methylene blue, centrifuging action and filtration, the absorbance of the solution was inversely proportional to the silanol quantity. The difference between the absorbance of the pure solution and that of the solid - free filtrate was related to the silica weight, yielding a quantitative analysis of these groups.

Scientific Electronic Library Online (Portuguese)

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Estado da arte da cromatografia gasosa de alta resolução e alta temperatura/ State of the art of high temperature high resolution gas chromatography

Pereira, Alberto dos Santos; Aquino Neto, Francisco Radler de
2000-06-01

Resumo em inglês The developments in stationary phase synthesis and capillary column technology, have opened new perspectives in analysis of high molecular mass compounds (³600 daltons) and thermolabile organic compounds by High Temperature High Resolution Gas Chromatography (HT-HRGC). HT-HRGC is a new analytical borderline and its application to the analysis of high molecular mass compounds is still in its infancy. The apolar and medium polar gum phases ca (mais) n now be operated at temperatures up to 400-480ºC, being used for the analysis of n-alcanes up to C-100, lipids, oligosaccharides, industrial resins, polyglycerols, cyclodextrins, porphyrins, etc. This technique should play a leading role as a powerful tool, for many different analysis types, in multidisciplinary fields of Science.

Scientific Electronic Library Online (Portuguese)

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Efeitos da beta-polinitração na eficiência catalítica de rutenioporfirinas em reações de oxidação de cicloexano/ Effects of beta-polynitration on the catalytic efficiency of rutheniumporphyrins in cyclohexane oxidation

Guimarães, Christian Alexander; Santos, Mirian Cristina dos; Moraes, Margarida de
2004-04-01

Resumo em inglês Rutheniumporphyrins, especially with several nitro groups in b-positions, were used in the cyclohexane oxidation in the presence of iodosylbenzene, hydrogen peroxide and sodium hypochlorite as oxygen donors, under mild conditions. The beta-polynitrated complexes were able to promote the catalytic cyclohexane oxidation. They show an exceptionally high catalytic efficiency and resistance to attack by strong oxidizing agents. The cyclohexane oxidation was monitored by gas ch (mais) romatography and the results showed that the beta-polynitrated rutheniumporphyrins are better catalysts when compared to other complexes not beta-polynitrated. In all cases, the 2-phenylsubstituted complexes were more efficient than 4-phenylsubstituted complexes. The importance of the ortho effect to oxidation was shown.

Scientific Electronic Library Online (Portuguese)

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Efeito do 1-metilciclopropeno sobre a emissão dos ésteres voláteis de bananas ao longo do amadurecimento/ Efferct of 1-MCP on esters volatiles eission of bananas along the ripening

Nascimento Junior, Baraquizio Braga do; Rezende, Claudia Moraes; Soares, Antônio Gomes; Fonseca, Marcos José de Oliveira
2008-01-01

Resumo em inglês Fresh green bananas (Musa sp., subgroup Prata) were treated with a dose of only 90 ηg g-1 of 1-MCP for 13 hours and the evolution of the volatile compounds along the ripeness was studied. A method to quantify the emission of esters was developed by cryogenic headspace and gas chromatography. Esters of acetate, butyrate, isobutyrate and isovalerate were found as major compounds. The application of the 1-MCP for 13 hours delayed the appearance of the coloration 8 of th (mais) e peel for 3 days and decreased quantitatively in about 46% the total production of esters in the banana until the 15° day of harvested.

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Efeito de matriz na quantificação de agrotóxicos por cromatografia gasosa/ Matrix effect in pesticide quantification by gas chromatography

Pinho, Gevany P.; Neves, Antônio A.; Queiroz, Maria Eliana L. R.; Silvério, Flaviano O.
2009-01-01

Resumo em inglês The lack of accuracy of a chromatographic method can be associated with the matrix effect. This effect is observed in pesticide quantification by gas chromatography when the chromatographic signals of standards prepared in solvents are compared with those of the analyte in extracts of complex matrices. In the competition between the matrix components and the pesticides for the active sites of the liner, a larger amount of pesticides is transferred to the column, giving ap (mais) parent extractions above 100%. In this work, we discuss factors that contribute to the matrix effect and present some attempts to overcome the problem.

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Determinação simultânea de trialometanos e agrotóxicos em água por cromatografia gasosa/ Determination of trihalomethanes and pesticides in water by gas chromatography

Carlos, Elenice A.; Neves, Antônio A.; Reis, César; Queiroz, Maria Eliana L. R. de
2011-01-01

Resumo em inglês A method for simultaneous analysis of trihalomethanes and organochloride and pyrethroid pesticides in water utilizing SPME-HS and GC-ECD was developed. In the optimized method 25 mL of water containing 2% (w/v) Na2HPO4 were heated to 60 °C for 50 min. The fiber (PDMS - 100 μm) was exposed to a headspace for the same period. For all analytes it was found that LOQ

Scientific Electronic Library Online (Portuguese)

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Determinação por cromatografia gasosa de açúcares em frutíferas de clima temperado/ Gas chromatography determination of sugars in temperate-zone fruit trees

Rodrigues, Alexandre Couto; Herter, Flávio Gilberto; Veríssimo, Valtair; Chavarria, Geraldo; Gardin, João Peterson Pereira; Campos, Ângela Diniz
2005-04-01

Resumo em português As frutíferas de clima temperado apresentam o fenômeno da dormência. Na saída da dormência, há a conversão do amido para açúcares solúveis, como substrato para a retomada de crescimento na primavera. Visando à maior compreensão da fisiologia das plantas em respostas a eventos, como as variações climáticas, estresses e problemas de adaptação, desenvolveu-se este trabalho, no Laboratório de Fisiologia Vegetal da Embrapa Clima Temperado, com o objetivo de d (mais) escrever uma metodologia para a determinação das concentrações dos açúcares solúveis (frutose, sorbitol, alfa-glicose, beta-glicose e sacarose), em tecidos vegetais de frutíferas, via cromatografia gasosa. O cromatógrafo utilizado para as análises dos açúcares por essa metodologia é o GAS CHROMATOGRAPH e a coluna do tipo Packed Column J. K. de 3,2mm de diâmetro por 2m de comprimento, empacotada com Silicone SE-52 Uniport HP 80/100 mesh. Através da cromatografia gasosa, obtêm-se eficiência e resolução cromatográfica, para análises de açúcares solúveis, sendo, desta forma, vantajoso e executável esse tipo de análise pelo método descrito. Resumo em inglês The temperate-zone deciduous fruit trees present the phenomenon of dormancy. In that period, there is the conversion of the starch in soluble sugars, as substratum for the resumption of growth in the spring. Seeking to better understanding the physiology of the plants in answers to events as the climatic variations, stresses and adaptation problems, this study was done in the Laboratory of Crop Physiology of Embrapa Temperate Climate, with the objective of describing a me (mais) thodology for determination of concentrations of the soluble sugars (fructose, sorbitol, alpha-glucose, beta-glucose and sucrose), in tissues of fruit tree, through gaseous chromatography. The chromatograph used for the analyses of the sugars was the GAS CHROMATOGRAPH with the column of the type Packed Column J. K. of 3,2mm of diameter for 2m of length packed with Silicon IF-52 Uniport HP 80/100 mesh. Through the gaseous chromatography it is obtained efficiency and chromatographic resolution to soluble sugars determination, being this way, advantageous to use this methodology.

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Determinação do teor de ésteres graxos em biodiesel metílico de soja por cromatografia gasosa utilizando oleato de etila como padrão interno/ Fatty ester content determination in soybean methyl biodiesel by gas chromatography using ethyl oleate as internal standard

Marques, Marcelo Volpatto; Naciuk, Fabrício Fredo; Mello, Ana Maria de Souza; Seibel, Nair Maria; Fontoura, Luiz Antonio Mazzini
2010-01-01

Resumo em inglês A method for ester content determination in soybean methyl biodiesel was studied, using ethyl oleate as internal standard. A biodiesel sample was analyzed and had its purity estimated as 92.8%. Method accuracy was evaluated by comparison with the result obtained via EN14103, with a relative difference of 0.1%. Repetitivity and intermediate precision were estimated as 2 and 1.5%, respectively.

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Determinação do perfil de compostos voláteis e avaliação do sabor e aroma de bebidas produzidas a partir da erva-mate (Ilex paraguariensis)/ Volatile compounds profile and flavor analysis of yerba mate (Ilex paraguariensis) beverages

Machado, Carla Carolina Batista; Bastos, Deborah Helena Markowicz; Janzantti, Natália Soares; Facanali, Roselaine; Marques, Marcia Ortiz M.; Franco, Maria Regina Bueno
2007-06-01

Resumo em inglês Volatile compounds from green and roasted yerba mate were analyzed by gas chromatography/mass spectrometry and the flavor profile from yerba mate beverages was determined by descriptive quantitative analyses. The main compounds tentatively identified in green mate were linalool, alpha-terpineol and trans-linalool oxide and in roasted mate were (E,Z)-2,4-heptadienal isomers and 5-methylfurfural. Green mate infusion was qualified as having bitter taste and aroma as well as (mais) green grass aroma while roasted mate was defined as having a smooth, slightly burnt aroma. The relationship between the tentatively identified compounds and flavor must be determined by olfatometric analysis.

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Determinação de ácidos carboxílicos em composto de resíduos sólidos urbanos por cromatografia gasosa com detector de ionização em chama/ Determination of volatile fatty acids in municipal solid waste compost by gas chromatography with flame ionization detection

Aquino, F. T.; Santiago-Silva, M.
2006-01-01

Resumo em português Um método simples e eficiente para determinação simultânea de quatro ácidos carboxílicos de cadeia curta (acético, propiônico, butírico e valérico) em resíduos sólidos urbanos (RSU) é descrito no presente trabalho. Estes ácidos são considerados fitotóxicos na literatura e a variabilidade das suas concentrações durante o processo pode ser usada como parâmetro da maturação do composto de resíduos sólidos urbanos (RSU). A determinação dos ácidos car (mais) boxílicos presentes no composto de RSU envolve uma extração em água e filtração em membranas de polifluoreto de vinilideno (PVDF), seguida da injeção direta em um cromatográfo a gás com detector por ionização em chama (CG-DIC). Foram analisados três tipos de leira. Boas linearidades e coeficientes de correlação foram obtidas para todos os ácidos, e os limites de detecção e quantificação foram baixos, resultando em um método sensível para monitoramento desses ácidos em composto de RSU. Resumo em inglês A simple and efficient method for the simultaneous gas chromatographic determination of four volatile fatty acids (acetic, propionic, butyric and valeric) in municipal solid waste (MSW) compost is described. This acids have been described as phytotoxic and the diversified concentrations of this acids could be used as a parameter of maturity of municipal solid waste compost (MSW). The determination of short chain carboxylic acids involves a single water extraction of these (mais) acids in the compost and filtration of the extracts with a polyvinylidine difluoride (PVDF) membrane prior to direct injection on a gas chromatograph with flame ionization detector (GC-FID). Three different piles of MSW were analyzed. Good linearity and good correlation coefficients were achieved for all compounds; furthermore, the detection and quantification limits were low, providing a sensitive method to monitoring these acids in MSW compost.

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Determinação de resíduos de pesticidas em plasma bovino por cromatografia gasosa-espectrometria de massas/ Pesticides residue determination in cattle plasma by gas chromatography-mass spectrometry

Maffei, Daniele Fernanda; Nogueira, Ana Rita de Araújo; Brondi, Silvia Helena Govoni
2009-01-01

Resumo em inglês An analytical method for the isolation based on matrix solid-phase dispersion technique and gas chromatographic determination of pesticides in cattle plasma is presented. It was fortified 0.25 g of plasma with pesticides and blended with 1 g each C18 and Na2SO4. The homogenized matter was transferred to a SPE cartridge, which contained 1 g of activated florisil with 5 mL acetonitrile. The analites were eluted under vaccum with 15 mL acetonitrile, the extract was analyzed (mais) by gas chromatography-mass spectrometry. The limit of quantification of the method was 0.04 mg L-1 for chlorphenvinfos and fipronil and 0.02 mg L-1 for cypermethrin..

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Determinação de isotiocianato de benzila em Carica papaya utilizando cromatografia gasosa com detectores seletivos/ Determination of benzyl isothiocyanate in Carica papaya using gas chromatography with selectives detectors

Castro, Izabela Miranda de; Anjos, Marianna Ramos dos; Oliveira, Elba dos Santos de
2008-01-01

Resumo em inglês In the present work, a method was developed and validated for the quantification of benzyl isothiocyanate (BITC) in the fruits of Carica papaya. The quantification of this compound was carried out by gas chromatography (GC) with selective detectors - nitrogen phosphorus detector (NPD) and flame photometric detector (FPD). The performance of these detectors showed a higher sensitivity of the NPD with a broader linear range of detection. The LOD/LOQ were 0.038/0.100 µg/mL (mais) for NPD and 5.78/19.29 µg/mL for FPD. The recovery of the method for BITC was 90,64%. An average value of BITC concentration in all the analyzed samples was 16,23 µg BITC/g.

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Determinação de hidrocarbonetos voláteis e semi-voláteis na atmosfera/ Determination of volatile and semi-volatile hydrocarbons in the atmosphere

Alves, Célia; Pio, Casimiro; Gomes, Paulo
2006-06-01

Resumo em inglês This paper focuses: (i) the development of a measurement technique for the determination of atmospheric C2-C6 hydrocarbons with sampling in canisters and analysis by gas chromatography/flame ionisation detector (GC/FID), (ii) the improvement of an existent adsorption-sampling technique with Tenax TA tubes for the determination of C6-C11 hydrocarbons and analysis by GC/FID after thermal desorption and cryogenic concentration, (iii) the identification of compounds present i (mais) n ambient air by gas chromatography/mass spectrometry (GC/MS) for both canister and Tenax samples, (iv) a program of interlaboratorial comparison for quality control of C2-C11 analyses, and (v) the seasonal characterisation of ambient air C2-C11 hydrocarbons.

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Determinação de esteróides androgênicos anabólicos em urina por cromatografia gasosa acoplada à espectrometria de massas/ Detection of androgenic anabolic steroids (AAS) in urine samples by gas chromatography-mass spectrometry

Campos, Daniel Rossi de; Yonamine, Mauricio; Alves, Maria Janieire de Nazaré Nunes; Moreau, Regina Lucia de Moraes
2005-12-01

Resumo em português Esteróides androgênicos anabólicos (EAA) são substâncias naturais, sintéticas ou semi-sintéticas derivadas da testosterona, utilizadas em atividades esportivas com o objetivo de melhorar o desempenho físico pelo aumento de massa e força muscular. Apesar de causarem efeitos tóxicos graves, principalmente sobre os sistemas cardiovascular, hepático e neuro-endócrino, os EAA têm sido amplamente utilizados no âmbito esportivo. Desta forma, o presente trabalho tev (mais) e como objetivo a validação de um método para a determinação de esteróides e/ou seus produtos de biotransformação em amostras de urina por cromatografia gasosa acoplada à espectrometria de massas (CG-EM). O método baseou-se na hidrólise enzimática de esteróides conjugados, no emprego da extração líquido-líquido e na derivação do extrato para posterior análise por CG-EM, no modo de monitoramento seletivo de íons (SIM). O método validado cumpriu com os princípios de confiança necessários para a determinação de EAA em amostras de urina com a finalidade de controle de dopagem no esporte. Os limites de detecção dos esteróides analizados variaram de 0,5 a 15 ng/mL. Bons valores de precisão (intra e interensaio) também foram obtidos (CV Resumo em inglês Androgenic anabolic steroids (AAS) are defined as natural, synthetic or semi-synthetic drugs chemically derived from testosterone, used with the aim to improve physical performance by increasing both muscle strength and mass. Despite their reported toxicological effects on the cardiovascular, hepatic and neuro-endocrine systems, the AAS have been extensively used in sports activities. The objective of this study was to validate an analytical method for the detection of AA (mais) S and/or their metabolites in urine samples. The method was based on enzymatic hydrolysis, liquid-liquid extraction, derivatization and further analysis by gas chromatography-mass spectrometry (GC-MS) operated in the selected ion monitoring mode (SIM). The validated method agrees with the confidence concepts for AAS detection in urine samples for anti-doping control programs. The limits of detection of AAS varied from 0,5 to 15ng/mL. Good inter and intra-assay precisions were also observed (CV

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Determinação da relação siringila/guaiacila da lignina em madeiras de eucalipto por pirólise acoplada à cromatografia gasosa e espectrometria de massas (PI CG/EM)/ Determination of the siringyl/guaiacyl ratio in eucalyptus wood by pyrolysis-gas chroma-tography/mass spectrometry (PY-GC/MS)

Barbosa, Luiz C. A.; Maltha, Célia R. A.; Silva, Vanessa Lopes; Colodette, Jorge Luiz
2008-01-01

Resumo em inglês The use of analytical pyrolysis combined with gas chromatography/mass spectrometry (Py-GC/MS) to determine the syringyl/guaiacyl ratio (S/G) in lignins from Eucalyptus spp woods was investigated. Sample of E. grandis and "E. urograndis" wood, with and without extractives, were subjected to pyrolysis from 300 ºC to 600 ºC. The products that results from pyrolysis were identified by mass spectrometry and the S/G ratio was determined based on the areas of the peaks corresp (mais) onding to the guaiacyl and syringyl derivatives. The best S/G estimation is achieved when pyrolysis is carried out at 550 ºC. Extractives and carbohydrate present in the woods do not interfere with the results.

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Determinação da matéria-prima utilizada na produção do biodiesel adicionado ao diesel mineral através de monitoramento seletivo de íons/ Determination of biodiesel raw materials in mineral diesel fuel using selective ion monitoring

Rocha, Daniel de Queiroz; Barros, Diana Kelly; Costa, Everton José Cardoso; Souza, Katiuscia S. de; Passos, Raimundo R.; Veiga Junior, Valdir Florêncio da; Chaar, Jamal da Silva
2008-01-01

Resumo em inglês The selective ion monitoring acquisition mode in mass spectrometry was applied to identify, in the diesel complex matrix, the raw materials (vegetable oil and alcohol) that originate biodiesel. Biodiesel samples obtained from babassu, castor, palm and soybean vegetable oils and pure fatty acid methyl and ethyl esters were used to develop this method, using specific fragments in mass spectrometry and the "window system" in gas chromatography. The commercial Brazilian B2 samples were found to be produced with soybean oil, transesterified with methanol.

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Desenvolvimento e validação de método de análise de glifosato em grãos de soja/ Development and validation of a method of analysis of glyphosate in soy grains

Abreu, Adley Bergson Gonçalves de; Matta, Marcia Helena de Rizzo da; Montagner, Émerson
2008-01-01

Resumo em inglês The main objective of this work is to develop an efficient procedure to determine glyphosate in soybean grains. The cleanup of the aqueous extracts was done in two steps, beginning with liquid-liquid partitioning and then solid-phase extraction with anion exchange resin. After derivatization with a mixture of trifluoroacetic anhydride (TFAA) and trifluoroethanol (TFE), quantification was done by gas chromatography coupled to mass spectrometry. The mean recovery and RSD of (mais) the spiked samples were, respectively, 80.5% and 3.1% at level 0.200 mg kg-1, 93.3% and 18.7% at level 0.500 mg kg-1 and 92% and 3.5% at level 1.000 mg kg-1. The method was linear in the working range (correlation coefficient = 0.9965).

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Desenvolvimento e validação de metodologia de análise de misturas biodiesel: diesel utilizando cromatografia gasosa-espectrometria de massas/ Development and validation of a methodology FOR analysis of biodiesel: diesel blends using gas chromatography-mass spectrometry

Faria, Rita C. M.; Rezende, Michelle J. C.; Rezende, Claudia M.; Pinto, Angelo C.
2007-01-01

Resumo em inglês The aim of this work was to develop and validate a method of analysis of biodiesel:diesel blends using HRGC-MS in SIM mode. The proposed method is applicable to biodiesel from linoleic oils, such as soybean oil. The following results were obtained: linearity over the methyl linoleate concentration range of 250-2500 mg L-1 (R² > 0.999); limits of detection and quantification of 2 and 5 mg L-1, respectively; recovery from 82 to 96% of biodiesel in diesel and repeatability

Scientific Electronic Library Online (Portuguese)

71

Desenvolvimento e aplicação de método GC-MS/MS para análise simultânea de 17 HPAs em material particulado atmosférico/ Development and application of GC-MS/MS method for simultaneous analysis of 17 PAHs in airborne particulate matter

Cristale, J.; Silva, F. S.; Marchi, M. R. R.
2008-12-01

Resumo em português Os hidrocarbonetos policíclicos aromáticos (HPAs) estão associados ao aumento da incidência de diversos tipos de cânceres no homem. Essas moléculas são formadas principalmente na queima incompleta de matéria orgânica, sendo encontradas em todos os compartimentos ambientais. Órgãos regulamentadores das áreas ambiental e de saúde ocupacional consideram 17 HPAs como contaminantes atmosféricos prioritários. Este trabalho apresenta um método para análise simul (mais) tânea destes HPAs utilizando-se a cromatografia a gás acoplada à espectrometria de massas operando no modo tandem (GC-MS/MS). Os limites de detecção e quantificação do método mostraram-se até 5 vezes inferiores aos obtidos no método GC-MS (SCAN). O método mostrou-se seletivo para análise de HPAs em extratos de amostras de material particulado atmosférico. Uma análise comparativa de dois sistemas de solventes (diclorometano/metanol 4:1 v/v e hexano/acetona 1:1 v/v) para a extração de HPAs, utilizando amostras de material particulado atmosférico, revelou que ambas as misturas de solventes possuem poder de extração semelhante. Os resultados sugerem que é possível realizar extração de HPAs de material particulado atmosférico em ultra-som com a mistura hexano/acetona (1:1), que é menos tóxica em relação à mistura diclorometano/metanol (4:1), bastante utilizada nestas análises, sem perdas significativas na exatidão do método. Resumo em inglês Polycyclic aromatic hydrocarbons (PAHs) are associated with increased incidence of various types of cancers in humans. These molecules are formed mainly in the incomplete burning of organic matter and can be found in all environmental compartments. North American regulatory agencies for environmental and occupational health areas consider 17 PAHs as air contaminants having priority. This work presents a method for simultaneous analysis of these PAHs using gas chromatograp (mais) hy coupled to mass spectrometry, operating in tandem mode (GC-MS/MS). The limits of detection and quantification of this method were 5 times lower than that obtained with GC-MS (SCAN) method. The method was selective in analysis of PAHs from airborne particulate matter. A comparative analysis of two systems of solvents (dichloromethane/methanol (4:1 v / v) and hexane/acetone (1:1 v / v)) for PAHs extraction, using samples of airborne particulate matter, shows that both mixtures of solvents have similar extraction ability. The results pointed out that it is possible to extract PAHs from airborne particulate matter using a mixture hexane/acetone (1:1), which is less toxic in than dichloromethane/methanol (4:1), usually used in these analyses, without significant losses in the accuracy of the method.

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Desenvolvimento de um método de MEFS com CG-DIC para determinação de 1,4 dioxana em amostras de cosméticos/ Soilid-phase microextraction method for the determination of 1,4 dioxane in cosmetics

Silva, Fernando C.; Faria, Cintia G.; Gabriel, Geraldo M.; Cardeal, Zenilda de L.
2001-12-01

Resumo em inglês A headspace solid-phase microextraction (HS-SPME) for the determination of 1,4 dioxane in cosmetics by gas chromatography is described. A manual SPME holder with 85 µm polyacrylate coating is utilized. The method is determined to have good resolution, satisfactory linerity (correlation coefficient r=0.997 for 0.20-10.00 mg Kg-1 range), a relative standard deviation of 6.3% and a detection limit of 5.00 µg Kg-1. Some cosmectic products were analyzed.

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Desenvolvimento de métodos analíticos para determinação de agrotóxicos em sedimentos por cromatografia gasosa monodimensional e bidimensional abrangente com micro detector de captura de elétrons/ Development of analytical methods for pesticides in sediments by monodimensional and comprehensive two-dimensional gas chromatography with micro electron-capture detection

Silva, Juliana Macedo da; Zini, Cláudia Alcaraz; Caramão, Elina Bastos; Canizares, Ewelin Monica Paturi Navarro; Leal, Karen Alam
2010-01-01

Resumo em inglês The development of analytical methods for determination of eight pesticides of different chemical classes (trichlorfon, propanil, fipronil, propiconazole, trifloxystrobin, permethrin, difenoconazole and azoxystrobin) in sediments with gas chromatography-micro-electron capture detector (GC/µECD) and comprehensive two-dimensional gas chromatography with micro-electron capture detector (GCxGC/µECD) is described. These methods were applied to real sediment samples, and the (mais) best results were obtained using a 5% diphenyl-methylpolysiloxane column for 1D-GC. For GCxGC the same column was employed in the first dimension and a 50%-phenyl-methylpolysiloxane stationary phase was placed in the second dimension. Due to the superior peak capacity and selectivity of GCxGC, interfering matrix peaks were separated from analytes, showing a better performance of GCxGC.

Scientific Electronic Library Online (Portuguese)

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Desenvolvimento de metodologia analítica para determinação de colesterol em ração para ruminantes através de planejamento experimental fatorial/ Development of an analytical method for cholesterol determination in feed for ruminants using factorial experimental design

Bandeira, Cecília Muller; Ferreira, José Maria; Bragagnolo, Neura; Mariutti, Lilian Regina Barros
2008-01-01

Resumo em inglês A chromatographic method was developed for cholesterol determination in feed for ruminants using response surface methodology. Among the five approaches of sample preparation methods tested, the saponification of the sample without heating presented less interference in the gas chromatography. The method presented a relative standard deviation (RSD) of 4.3%, recoveries between 84 and 87% and detection limit of 0.001 mg of cholesterol per g of feed.

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Degradação e estabilização do diclofenaco em nanocápsulas poliméricas/ Degradation and stabilization of diclofenac in polymeric nanocapsules

Müller, Claudia Regina; Haas, Sandra Elisa; Bassani, Valquíria Linck; Guterres, Sílvia Stanisçuaski; Fessi, Hatem; Peralba, Maria do Carmo R.; Pohlmann, Adriana Raffin
2004-08-01

Resumo em inglês The parameters which affect the degradation and stabilization of diclofenac in suspensions of nanocapsules and of the corresponding spray-dried powders were investigated. Formulations were subjected to 14 months of storage at room temperature. In addition, a study of the degradation of diclofenac was carried out by exposing the formulations or mixtures (drug and adjuvants) to UVC wavelengths. The presence of Epikuron 170® in a concentration higher than 3.06 mg/mL stabili (mais) zes the drug, avoiding its reduction or degradation. The degradation products were isolated, analyzed by gas chromatography-mass spectrometry, and identified as 2-(2',6'-dichlorophenyl)aminobenzyl alcohol and N-(2',6'-dichlorophenyl)anthranilylaldehyde.

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Controle de autenticidade de óleos de copaíba comerciais por cromatografia gasosa de alta resolução/ Authenticity control of commercial copaiba oils by high resolution gas chromatography

Veiga Jr., Valdir F.; Patitucci, Maria Lucia; Pinto, Angelo C.
1997-12-01

Resumo em inglês Copaiba oil is a resin extracted from the trunk of trees of Copaifera species which grow in Brazil where it is widely used in popular medicine as an anti-inflammatory, antiseptic anti-bactericidal, diuretic, dermatological, expectorant, and anti-infective. The comparative study of the composition of commercial copaiba oils was carried out by high resolution gas chromatography (HRGC) and high resolution gas chromatography-mass spectrometry (HRGC-MS) analysis. The commercia (mais) l oils were compared with authentic oils, collected from the southeast and northern regions of Brazil. Sixteen commercial oils were analysed and two of them revealed adulterations with fatty acids. Using the chromatographic profile of authentic copaiba species oils, it is possible to analyse commercial oils and determine the authenticity of these materials.

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Constituintes voláteis do fruto do pajeuzeiro (Triplaris sp.)/ Volatile constituents of pajeuzeiro fruit (Triplaris sp.)

Carneiro, Júlia Geracila de Mello e; Cito, Antonia Maria das Graças Lopes; Pessoa, Eliana de Freitas
2010-09-01

Resumo em português O estudo dos constituintes voláteis dos frutos contribui para a indicação destes para diferentes aplicações, como nas indústrias alimentícia, farmacêutica e de cosméticos. A importância da pesquisa de componentes voláteis em frutos silvestres reveste-se no fato de que esses resultados apontem para o seu aproveitamento, assim como para despertar o interesse de produtores para o seu cultivo comercial. O trabalho teve como objetivo a identificação dos constituin (mais) tes voláteis do óleo essencial dos frutos de pajeuzeiro (Triplaris sp.). As atividades foram conduzidas no Núcleo de Estudos, Pesquisas e Processamento de Alimentos do Centro de Ciências Agrárias da Universidade Federal do Piauí, em Teresina-PI. Os frutos foram colhidos no município de Beneditinos-PI. Na extração do óleo essencial, utilizou-se a técnica de hidrodestilação, e a identificação dos constituintes foi realizada por cromatografia gasosa / espectrometria de massas - CG/EM. Identificaram-se 8 (oito) das 12 (doze) substâncias extraídas, tendo como constituintes majoritários: palmitato de metila (21,67%) e 10-octadecenoato de metila (21,72%). Resumo em inglês The study of volatile constituents of the fruit contributes to the indication for different applications such as in food, pharmaceutical and cosmetics. The importance of research volatile compounds in berries is of the fact that these results point to their use, and to arouse the interest of producers for its commercial cultivation. The objective of this work was to the identification of volatile constituents of essential oil of fruits of the pajeuzeiro (Triplaris sp.). T (mais) he activities were conducted in the Centro de Ciências Agrárias - CCA of the Universidade Federal do Piauí, Teresina, PI city. The fruits were collected in the of Beneditinos, PI city. In the extraction of essential oil it was used the technique of hydrodistillation and the identification of constituents was performed by gas chromatography / mass spectrometry - GC/MS. It was observed 8 (eight) of 12 (twelve) substances extracted with the major constituents: the methyl palmitate (21.67%) and 10-octadecenoate of methyl (21.72%).

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Comprehensive Two-Dimensional Gas Chromatography for Fingerprint Pattern Recognition in Olive Oils Produced by two Different Techniques in Portuguese Olive Varieties Galega Vulgar, Cobrançosa e Carrasquenha

Costa Freitas, Ana Maria; Gomes da Silva, Marco; Vaz-Freire, Luis Torres

O artigo aplica a Cromatografia multidimensional para a caracterixzação de voláteis em azeites de variedades portuguesas, aplicando um software de reconhecimento de imagem Image J

DRIVER (Portuguese)

79

Compostos voláteis de três cultivares de manga (Mangifera indica L.)/ Volatile composition of three cultivars of mango (Mangifera indica L.)

Franco, M.R.B.; Rodriguez-Amaya, D.; Lanças, F.M.
2004-06-01

Resumo em português Os compostos voláteis de três cultivares de manga (Haden, Tommy-Atkins e Keitt) procedentes do Estado de São Paulo, foram isolados por uma técnica de headspace dinâmico, envolvendo sucção em polímero poroso. A separação da mistura complexa de voláteis foi efetuada por cromatografia gasosa de alta resolução. Alguns compostos voláteis foram identificados por cromatografia gasosa-espectrometria de massas e índices de Kovats. Os hidrocarbonetos monoterpênicos (mais) foram os compostos mais abundantes no headspace das amostras. Car-3-eno foi o componente majoritário dos cultivares Haden e Keitt, enquanto a Tommy-Atkins mostrou predominância de car-3-eno e alfa-pineno. Outros compostos identificados foram alfa-fencheno, alfa-canfeno, p-cimeno, beta-mirceno, beta-felandreno, limoneno, alfa-terpinoleno, beta-cariofileno e alfa-humuleno. Os três lotes analisados para cada cultivar mostraram grande homogeneidade, não havendo diferença significativa ao nível de 5%. Resumo em inglês The volatile compounds of three mango cultivars (Haden, Tommy-Atkins and Keitt), from the State of São Paulo, were isolated by a dynamic headspace technique involving suction on a porous polymer. The complex mixture of volatile compounds was separated by high-resolution gas chromatography. Some volatiles were identified by gas chromatography-mass spectrometry and Kovats Indices. The monoterpene hydrocarbons were the most abundant in the headspace of the fruits. Car-3-ene (mais) was the major component of the cultivars Haden and Keitt, while the Tommy Atkins mango exhibited predominance of two constituents, car-3-ene and alpha-pinene. Other identified compounds were alpha-fenchene, alpha-camphene, p-cimene, beta-mircene, beta-phellandrene, limonene, alpha-terpinolene, beta-caryophyllene e alpha-humulene. Samples of the same cultivar demonstrated great homogeneity, with no statistically significant difference being observed among the three lots analyzed for each cultivar.

Scientific Electronic Library Online (Portuguese)

80

Composição química da glândula abdominal da fêmea da mariposa Castnia licus (Drury) (Lepidoptera:Castniidae): possíveis feromônios e precursores/ Chemical composition from female pheromone gland of Castnia licus (Drury) (Lepidoptera: Castniidae)

Rebouças, Lúcia M. C.; Caraciolo, Maria do S. B.; Sant'Ana, Antônio E. G.; Pickett, John A.; Wadhams, Lester J.; Pow, Eleanor M.
1999-09-01

Resumo em inglês The hexane and methanolic extracts from pheromonal glands of Castnia licus (Drury) virgin females have been studied. Analyses by gas chromatography and mass spectrometry allowed us to determine the major constituents present in the hexane extract as n-alkanes C21 to C30, (Z)-9-hexadecenoic acid (C16), and (Z)-9-octadecenoic acid (C18) and hexadecanoic acid (C16). Aldehyds, alkenes and acetates were also detected in low concentrations in the extracts. Female pheromone glan (mais) ds were analysed for pheromone precursors using the methanolic extract. In addition to the compounds methyl hexadecanoate and methyl (Z)-9-octadecenoate, the glandular tissue contains a homologous series of methyl esters from C12 to C24. The hexane extract of the female abdomenal glands elicited activity from males in a behavioural bioassay.

Scientific Electronic Library Online (Portuguese)

81

Composição molecular e origem paleobotânica de âmbares da bacia do Araripe, Formação Santana/ Molecular composition and paleobotanical origin of ambers from the Araripe basin, Santana Formation

Pereira, Ricardo; Carvalho, Ismar de Souza; Fernandes, Antônio Carlos Sequeira; Azevedo, Débora de Almeida
2009-01-01

Resumo em inglês The terpenoid composition of seven amber samples from Araripe Basin (Santana Formation, Crato Member) has been analyzed by gas chromatography-mass spectrometry to determine their botanical origin. The diterpenoids, which have been identified in the fossil resin extracts are derived primarily from the abietane class, e.g., dehydroabietane, 4-epidehydroabietol, 16,17,18-trisnorabieta-8,11,13-triene, 7-oxo-16,17,19-trisnorabieta-8,11,13-trieno, dehydroabietic acid, ferrugino (mais) l, hinokiol and hinokione. Their composition is certainly typical for conifers, and angiosperms can be excluded as the botanical source, as no triterpene was identified. The terpenoid characteristics strongly support a relationship to the Araucariaceae or Podocarpaceae families. In addition, the fossil record of the embedding sediments (pollen and fossil leaves) also supports the proposal of these paleobotanical origins for the ambers.

Scientific Electronic Library Online (Portuguese)

82

Compatibilidades e incompatibilidades entre radiação gama e óxido de etileno como métodos sucessivos de esterilização/ Compatibilities and incompatibilities between gamma rays and ethylene oxide as consecutive sterilization methods/ Compatibilidades e incompatibilidades entre rayos gama y óxido de etileno como métodos sucesivos de esterilización

Souza, Rafael Queiroz de; Graziano, Kazuko Uchikawa
2010-12-01

Resumo em português A dúvida sobre a questão da re-esterilização de artigos confeccionados com cloreto de polivinila (PVC), esterilizados em radiação gama (RG) e posteriormente em óxido de etileno (EO) persiste até os dias atuais. Por meio da revisão integrativa da literatura, este artigo analisou estudos que evidenciaram compatibilidades e incompatibilidades entre os processos de esterilização com RG e EO quando utilizados como métodos sucessivos de esterilização. Foram analis (mais) ados 7 estudos. Constatou-se que há influência multifatorial na segurança do procedimento e que o método analítico da cromatografia empregado na maioria dos estudos produziu resultados controversos. Esse fato indica a necessidade da realização de novos estudos sobre o assunto, utilizando-se métodos analíticos mais sensíveis do que a cromatografia gasosa, como o teste de reatividade biológica em culturas celulares, que poderá dirimir em nosso meio a crônica dúvida da compatibilidade ou incompatibilidade de se esterilizar em EO materiais previamente gamairradiados. Resumo em espanhol La duda sobre la cuestión de la reesterilización de artículos confeccionados con policloruro de vinilo (PVC) esterilizados con Rayos Gamma (RG) y posteriormente en óxido de etileno (EO) persiste hasta la actualidad. A través de la revisión integradora de la literatura, este artículo analizó estudios que evidenciaron compatibilidades e incompatibilidades entre los procesos de esterilización con RG y EO, cuando se utilizan en forma sucesiva. Fueron analizados 7 est (mais) udios. Se constató que hay influencia multifactorial en la seguridad del procedimiento y que el método analítico de cromatografía empleado en la mayoría de los estudios generó resultados controversiales. Este hecho indica la necesidad de realizar nuevos estudios sobre el asunto, utilizando métodos analíticos más sensibles que la cromatografía gaseosa, tales como el test de reactividad biológica en cultivos celulares para dirimir en nuestro medio la crónica duda de la compatibilidad o incompatibilidad de esterilizar en EO materiales previamente irradiados con Rayos Gamma. Resumo em inglês The doubt regarding the re-sterilization of articles made of polyvinyl chloride (PVC) sterilized with gamma radiation (GR) and subsequently with ethylene oxide (EO) persists to date. Through a systematic literature review, this article analyzed studies that demonstrated compatibilities and incompatibilities between the sterilization processes with GR and EO, when used as consecutive sterilization methods. Seven studies were analyzed. It was verified that there is a multif (mais) actor influence regarding the safety of the procedure and that the chromatography analytical method employed by most studies yielded controversial results. This fact indicates the need for further studies on the issue, using more sensitive analytical methods than gas chromatography, such as the biological reactivity test in cell cultures, in an attempt to clarify the chronic doubt regarding the adequacy or inadequacy of sterilizing previously gamma-irradiated materials with EtO.

Scientific Electronic Library Online (Portuguese)

83

Comparação entre métodos de quantificação em cromatografia gasosa: um experimento para cursos de química/ Comparison of quantification methods in gas chromatography: an experiment for chemistry courses

Ligiero, Carolina Bastos Pereira; Reis, Lindomar Augusto dos; Parrilha, Gabrieli Lessa; Baptista Filho, Milton; Canela, Maria Cristina
2009-01-01

Resumo em inglês This article describes an experiment designed to teach quantitative determination in gas chromatography (GC) in Organic and Analytical Chemistry practical classes. The experiment consisted of extracting and analyzing eugenol from clove seeds to perform a quantitative approach aimed at comparing results obtained by external and internal calibration procedures. Therefore, this experiment proved to be very effective tool to enhance students awareness on the need to understan (mais) d different types of calibration in GC and on how to avoid common experimental errors, and to find the best ways to eliminate their interference during the quantitative analysis phase.

Scientific Electronic Library Online (Portuguese)

84

Comparação entre injeção na coluna ("on-column") e headspace dinâmico na determinação de benzeno, tolueno e xilenos (BTX) em amostras de água/ Comparison between on-column injection and dynamic headspace in the determination of Benzene, Toluene and Xylene (BTX) in water

Gobato, Elaine A. A. F.; Lanças, Fernando M.
2001-04-01

Resumo em inglês The analysis of water samples containing volatile organic compounds has become an important task in analytical chemistry. Gas chromatography has been widely used for the analysis of volatile organic compounds in water. The headspace analysis shows as a principal characteristic the possibility of determination of the volatile components in drinking water. Benzene, Toluene and Xylene (BTX) are important compounds usually present in drinking water, from contamination by petr (mais) oleum derivatives. Since they are toxic compounds even when present in low concentration levels, their determination is important in order to define the quality of the water. The sampling technique using headspace, coupled with gas chromatography as the separation method, showed to be suitable for BTX analysis in several samples at the mug/L (ppb) level.

Scientific Electronic Library Online (Portuguese)

85

Comparação de diferentes abordagens para avaliação da incerteza na cromatografia gasosa do gás natural/ Comparison of different approaches to evaluate the uncertainty of gas chromatography for natural gas

Oliveira, Elcio Cruz de; Aguiar, Paula Fernandes de
2009-01-01

Resumo em inglês The evaluation of uncertainty associated with an analytic result is an essential part of the measurement process. Recently, several approaches to evaluate the uncertainty in measurement have been developed. Here, the gas chromatography assay uncertainty for natural gas is compared by some of these approaches: the guide to the expression of uncertainty in measurement (GUM) approach, top-down approach (reproducibility estimate from an inter-laboratory study), Barwick & Elli (mais) son (data from validation), study of variability and fuzzy approach. The comparison shows that GUM, Barwick & Ellison and fuzzy approaches lead to comparable uncertainty evaluations, which does not happen with the top-down approach and study of variability by the absence of data normality.

Scientific Electronic Library Online (Portuguese)

87

Caracterização química de extratos de Ocimum basilicum L. obtidos através de extração com CO2 a altas pressões/ Chemical characterization of Ocimum basilicum L. extracts obtained by high pressure CO2 extraction

Mazutti, Marcio; Beledelli, Bernardo; Mossi, Altemir José; Cansian, Rogério Luís; Dariva, Cláudio; Oliveira, José Vladimir de; Paroul, Natália
2006-12-01

Resumo em inglês This work reports extraction yield and chemical characterization of the extracts obtained by high-pressure CO2 extraction of a cultivar of Ocimum basilicum L. The experiments were performed in the temperature range of 20 to 50 °C, from 100 to 250 atm of pressure. Chemical analyses were carried out by gas chromatography coupled to mass spectrometry, permitting to identify 23 compounds that were grouped into five chemical classes. Results showed that temperature and solven (mais) t density influenced positively the extraction yield. At 20 °C and 0.41 g cm-3 occurred a rise in the concentration of monoterpenes, oxygenated monoterpenes, sesquiterpenes and oxygenated sesquiterpenes.

Scientific Electronic Library Online (Portuguese)

88

Caracterização de amostras petroquímicas e derivados utilizando cromatografia gasosa bidimensional abrangente (GCxGC)/ Characterization of petrochemical samples and their derivatives by comprehensive two-dimensional gas chromatography

von Mühlen, Carin; Zini, Claudia Alcaraz; Caramão, Elina Bastos; Marriott, Philip J.
2006-07-01

Resumo em inglês The goal of this article is to discuss the application of comprehensive two-dimensional gas chromatography (GCxGC) to petrochemical samples. The use of GCxGC for petroleum and petroleum derivatives characterization, through group type analysis, or BTEX (benzene, toluene, ethylbenzene, xylenes), total aromatic hydrocarbons, polyaromatic hydrocarbons, sulfur-containing, oxygen-containing, and nitrogen-containing compounds is presented. The capability of GCxGC to provide add (mais) itional specific chemical information regarding petroleum processing steps, such as dehydrogenation of linear alkanes, the Fischer-Tropsch process, hydrogenation and oligomerization is also described. In addition, GCxGC analyses of petrochemical biomarkers and environmental pollutants derived from petrochemicals are reported.

Scientific Electronic Library Online (Portuguese)

89

Caracterização das emissões de aldeídos de veículos do ciclo diesel/ Emission of aldehydes from light duty diesel vehicles

Abrantes, Rui de; Assunção, João V de; Hirai, Edegar Yoshio
2005-06-01

Resumo em português OBJETIVO: Caracterizar as emissões de acetaldeído e formaldeído, substâncias nocivas para a saúde das pessoas e cujas emissões dos veículos a diesel ainda não estão regulamentadas. MÉTODOS: Testes padronizados foram realizados em quatro veículos leves comerciais do ciclo diesel, testados num dinamômetro de chassis, usando o procedimento de teste FTP-75. Os poluentes foram analisados por cromatografia líquida de alta eficiência. RESULTADOS: Os resultados most (mais) raram que a emissão de acetaldeído variou de 5,9 a 45,4 mg/km e a de formaldeído variou de 16,5 a 115,2 mg/km. A emissão média para a soma dos aldeídos foi de 58,7 mg/km, variando de 22,5 mg/km a 160 mg/km. A proporção entre os dois se manteve constante, próximo de 74% de formaldeído e 26% de acetaldeído. CONCLUSÕES: A emissão de aldeídos provenientes de veículos movidos a diesel foi significativa quando comparada com as emissões reais dos veículos de ignição por centelha ou com o limite previsto para os veículos do ciclo Otto na legislação brasileira. O estabelecimento de limites de emissão para essas substâncias para veículos a diesel mostra-se importante, considerando o crescimento da frota de veículos a diesel, a toxicidade desses compostos e sua participação como precursores nas reações de formação de gás ozônio na baixa troposfera. Resumo em inglês OBJECTIVE: To characterize acetaldehyde and formaldehyde emissions, which are harmful gases to human health and not yet regulated for diesel engines. METHODS: Standardized tests were performed in four diesel light duty commercial vehicles, using a frame dynamometer and test procedure FTP-75. The pollutants were analyzed by high performance liquid chromatography. RESULTS: Results have shown acetaldehyde emission ranged from 5.9 to 45.4 mg/km, and formaldehyde emission from (mais) 16.5 to 115.2 mg/km. The average emission for aldehyde sum was 58.7 mg/km, ranging from 22.4 to 160.6 mg/km. The proportion between the two substances remained constant, close to 74% for formaldehydes and 26% for acetaldehydes. CONCLUSIONS: The emission of diesel vehicle aldehydes was significant when compared with actual spark ignition vehicle emissions, or with the foresee limit for Otto cycle vehicles in Brazilian legislation. Establishing emission limits for these substances also in diesel vehicles is imperative in the light of the vehicle fleet growth, toxicity of these compounds, and their contribution as precursors in ozone gas formation reactions in low troposphere.

Scientific Electronic Library Online (Portuguese)

90

Caracterização das emissões de aldeídos de veículos do ciclo diesel/ Emission of aldehydes from light duty diesel vehicles

Abrantes, Rui de; Assunção, João V de; Hirai, Edegar Yoshio
2005-06-01

Resumo em português OBJETIVO: Caracterizar as emissões de acetaldeído e formaldeído, substâncias nocivas para a saúde das pessoas e cujas emissões dos veículos a diesel ainda não estão regulamentadas. MÉTODOS: Testes padronizados foram realizados em quatro veículos leves comerciais do ciclo diesel, testados num dinamômetro de chassis, usando o procedimento de teste FTP-75. Os poluentes foram analisados por cromatografia líquida de alta eficiência. RESULTADOS: Os resultados most (mais) raram que a emissão de acetaldeído variou de 5,9 a 45,4 mg/km e a de formaldeído variou de 16,5 a 115,2 mg/km. A emissão média para a soma dos aldeídos foi de 58,7 mg/km, variando de 22,5 mg/km a 160 mg/km. A proporção entre os dois se manteve constante, próximo de 74% de formaldeído e 26% de acetaldeído. CONCLUSÕES: A emissão de aldeídos provenientes de veículos movidos a diesel foi significativa quando comparada com as emissões reais dos veículos de ignição por centelha ou com o limite previsto para os veículos do ciclo Otto na legislação brasileira. O estabelecimento de limites de emissão para essas substâncias para veículos a diesel mostra-se importante, considerando o crescimento da frota de veículos a diesel, a toxicidade desses compostos e sua participação como precursores nas reações de formação de gás ozônio na baixa troposfera. Resumo em inglês OBJECTIVE: To characterize acetaldehyde and formaldehyde emissions, which are harmful gases to human health and not yet regulated for diesel engines. METHODS: Standardized tests were performed in four diesel light duty commercial vehicles, using a frame dynamometer and test procedure FTP-75. The pollutants were analyzed by high performance liquid chromatography. RESULTS: Results have shown acetaldehyde emission ranged from 5.9 to 45.4 mg/km, and formaldehyde emission from (mais) 16.5 to 115.2 mg/km. The average emission for aldehyde sum was 58.7 mg/km, ranging from 22.4 to 160.6 mg/km. The proportion between the two substances remained constant, close to 74% for formaldehydes and 26% for acetaldehydes. CONCLUSIONS: The emission of diesel vehicle aldehydes was significant when compared with actual spark ignition vehicle emissions, or with the foresee limit for Otto cycle vehicles in Brazilian legislation. Establishing emission limits for these substances also in diesel vehicles is imperative in the light of the vehicle fleet growth, toxicity of these compounds, and their contribution as precursors in ozone gas formation reactions in low troposphere.

Scientific Electronic Library Online (Portuguese)

91

Cafeína: revisão sobre métodos de análise/ Analytical methods for caffeine

De Maria, Carlos A. B.; Moreira, Ricardo F. A.
2007-02-01

Resumo em inglês Gravimetric and Bailey-Andrew methods are tedious and provide inflated results. Spectrofotometry is adequate for caffeine analysis but is lengthy. Gas chromatography also is applied to the caffeine analysis but derivatization is needed. High performance liquid chromatography with ultraviolet detection (HPLC-UV) and reversed phase is simple and rapid for xanthine multianalysis. In HPLC-UV-gel permeation, organic solvents are not used. HPLC-mass spectrometry provides an une (mais) quivocal structural identification of xanthines. Capillary electrophoresis is fast and the solvent consumption is smaller than in HPLC. Chemometric methods offer an effective means for chemical data handling in multivariate analysis. Infrared spectroscopy alone or associated with chemometries could predict the caffeine content in a very accurate form. Electroanalytical methods are considered of low cost and easy application in caffeine analysis.

Scientific Electronic Library Online (Portuguese)

92

CGAR E CGAR-EM na análise dos constituintes químicos isolados do extrato hexanico de Sebastiania argutidens (Euphorbiaceae)/ HRGC and HRGC-MS in the analysis of the chemical constituents isolated from hexanic extract of Sebastiania argutidens (Euphorbiaceae)

Branco, Alexsandro; Pizzolatti, Moacir G.
2002-02-01

Resumo em inglês The fractionation column with SiO2 of the hexane extract of Sebastiania argutidens (Euphorbiaceae) yielded fractions containing hydrocarbons, carboxylic acids, sterols and pentacyclic triterpenes. Besides, one fraction showed the presence of several methyl esters, including four uncommon long chain palmitate esthers as minor components. The characterization of these chemical constituents have been done by High Resolution Gas Chromatography (HRGC) and HRGC coupled to Mass (mais) Spectrometry (GC/MS). Campesterol, stigmasterol, b-sitosterol, glutin-5-en-3-ol were identified by HRGC co-injection with standards.

Scientific Electronic Library Online (Portuguese)

93

Bebida à base de flocos de abóbora com inulina: características prebióticas e aceitabilidade/ Drink based on pumpkin flakes containing insulin: prebiotic characteristics and acceptability

Silveira, Karina Correia da; Brasil, Jacira Antonia; Livera, Alda Verônica de Souza; Salgado, Silvana Magalhães; Faro, Zelyta Pinheiro de; Guerra, Nonete Barbosa
2008-06-01

Resumo em português OBJETIVO: Formular bebida para crianças de 4 a 6 anos, à base de flocos de abóbora adicionada de inulina, e caracterizá-la quanto ao valor nutricional, à aceitação e ao efeito prebiótico. MÉTODOS: O valor nutricional da bebida foi avaliado por meio de análise da umidade, de proteínas, lipídeos, cinzas, fibra alimentar, carboidratos e carotenóides. As características microbiológicas foram avaliadas por meio de análises de coliformes a 35ºC e a 45ºC, Staph (mais) ylococcus aureus, Salmonella ssp, Bacillus cereus, de contagem padrão de aeróbios, bolores e leveduras. A aceitabilidade foi determinada por testes sensoriais, aplicados em duas creches da região metropolitana do Recife (PE), o efeito prebiótico foi avaliado por fermentação in vitro, em meio diferencial para bactérias homefermentativas e heterofermentativas-Ágar, e as análises de ácidos graxos de cadeia curta, foram avaliadas por cromatografia a gás. RESULTADOS: Os resultados físico-químicos demonstram que as formulações pouco diferiram quanto à composição centesimal e que a ingestão 200mL/dia contribui, em média, com 10,8%, 36,0%, 10,2%, 12,6%, 37,1% e 126,4% da Recomendação de Ingestão Diária de energia, proteínas, carboidratos, lipídeos, fibra alimentar e carotenóides, respectivamente. Os resultados microbiológicos comprovaram a inocuidade do produto; os sensoriais que as formulações obtiveram uma aceitação em torno de 70% e os dados da avaliação do efeito prebiótico sugerem maior estudo sobre o tema. CONCLUSÃO: Os resultados permitem concluir que as formulações são nutricionalmente adequadas para pequenas refeições de crianças de 4 a 6 anos, pois, além de prevenir a carência de vitamina A apresentam indícios de efeitos prebióticos. Resumo em inglês OBJECTIVE: The objective of this study was to formulate a drink for kids aging from 4 to 6 years based on pumpkin seeds and with insulin, and characterize the drink regarding its nutritional value, acceptance and prebiotic effect. METHODS: The nutritional value of the drink was assessed by determining moisture, proteins, lipids, ash, dietary fiber, carbohydrates and carotenoids. The microbiological characteristics were assessed by coliform analysis at 35ºC and 45ºC, Sta (mais) phylococcus aureus, Salmonella ssp, Bacillus cereus, standard aerobic organism count, yeasts and molds. Acceptance was determined by sensory tests in two daycare units of the metropolitan region of Recife (PE). The prebiotic effect was assessed by in vitro fermentation in a differential medium for homofermentative and heterofermentative bacteria. Short chain fatty acids were determined by gas chromatography. RESULTS: The physical-chemical results showed that the formulations differed slightly regarding the centesimal composition and that the ingestion of 200mL/day contributes, on average, with 10.8%, 36.0%, 10.2%, 12.6%, 37.1% and 126.4% of the recommended daily intake of energy, proteins, carbohydrates, lipids, dietary fiber and carotenoids respectively. The microbiological results proved that the product is innocuous. The acceptance of the product was of roughly 70%. The results of the prebiotic effects showed that more research is necessary. CONCLUSION: The results allow us to conclude that the formulations are nutritionally adequate for small meals of children aging from 4 to 6 years, since the product not only avoids vitamin A deficiency but also presents evidence of some prebiotic effects.

Scientific Electronic Library Online (Portuguese)

94

Avaliação quantitativa de monoepoxiácidos, monocetoácidos e monohidroxiácidos em óleos e gorduras provenientes de fritura descontínua de batatas/ Quantitative evaluation of monoepoxyacids, monoketoacids and monohydroxyacids in fats and oils used in discontinuous frying of potatoes

Machado, Eliana Rodrigues; Marmesat, Susana; Dobarganes, María del Carmen; Abrantes, Shirley
2008-09-01

Resumo em português Na fritura, os óleos e gorduras sofrem degradação formando os compostos polares, como os triacilgliceróis polimerizados e os monômeros de triacilgliceróis oxidados, estes últimos têm sido relacionados a patologias e se constituem de grupos como os monoepoxiácidos, monocetoácidos e monohidroxiácidos. Foram determinados os teores destes três grupos de substâncias, através da análise cromatográfica a gás dos ésteres metílicos de ácidos graxos após deriva (mais) ção a frio das amostras e concentração posterior das substâncias de interesse mediante extração em fase sólida, e os teores dos ácidos graxos polares polimerizados, utilizando a combinação das técnicas cromatográficas de adsorção em coluna e por exclusão, em gordura de soja parcialmente hidrogenada e óleos de soja e de palma, aquecidos a 180 °C por 25 horas, provenientes de experimentos de fritura. Foram encontrados teores de 3,30 a 8,24; 1,51 a 4,32 e 3,42 a 8,71 mg.g-1 de monoepoxiácidos, monocetoácidos e monohidroxiácidos, respectivamente, nas amostras com níveis de compostos polares de 20,8 a 44,1% (m/m), e predominância de formação de polímeros. Os resultados sugeriram que óleos e gorduras monoinsaturados apresentam maior tendência à formação de monômeros oxidados e menor tendência à formação de polímeros, ao contrário dos óleos poliinsaturados. Resumo em inglês During frying, fats and oils undergo degradation with the formation of polar compounds. Among these are polymeric triglycerides, as well as oxidized monomeric triglycerides. The last group has been related to several diseases and contains groups including epoxy, keto and hydroxy groups of importance from a quantitative point of view. In this study, monoepoxyacids, monoketoacids and monohydroxyacids were quantified in partially hydrogenated soybean oil, soybean oil and pal (mais) m oil, after heating for 25 hours, at 180 °C, in frying experiments. The determination was carried out by gas chromatography after fat derivatization to fatty acid methyl esters at room temperature and concentration of the compounds of interest by solid phase extraction on silica cartridges. Quantitative analyses of polar fatty acids were also obtained by combination of adsorption and size exclusion chromatography. The major content corresponded to polymeric compounds. Amounts ranging from 3.30 to 8.24; from 1.51 to 4.32 and from 3.42 to 8.71 mg.g-1 were found for monoepoxyacids, monoketoacids and monohydroxyacids, respectively, for samples containing polar compounds between 20.8 and 44.1%. The results suggested that monounsaturated oils have a higher tendency to the formation of oxidized monomers while polyunsaturated oils have a higher tendency to the formation of polymers.

Scientific Electronic Library Online (Portuguese)

95

Atividade antioxidante de óleos essenciais de espécies de Croton do nordeste do Brasil/ Antioxidant activity of essential oils from Northeastern Brazilian Croton species

Morais, Selene Maia de; Catunda Júnior, Francisco Eduardo Aragão; Silva, Ana Raquel Araújo da; Martins Neto, Jason Stone; Rondina, Davide; Cardoso, José Henrique Leal
2006-10-01

Resumo em inglês Three Croton species, C. zenhtneri, C. nepetaefolius and C. argyrophylloides, were collected at two different times, 6:00 and 13:00 h, their essential oils were extracted by steam distillation and analyzed by gas Chromatography / Mass Spectrometry. The percentage yield of oil constituents changes along the day. The oils were submitted to the antioxidant test thiobarbituric acid reactive species, using BHT and a-tocoferol as the reference compounds. All oils exhibited good (mais) antioxidant activities. In general, C. zenhtneri and C. argyrophylloides essential oils showed higher antioxidant activity than C. nepetaefolius.

Scientific Electronic Library Online (Portuguese)

96

Aplicação da técnica de dispersão da matriz em fase sólida (DMFS) na análise de pesticidas em quiabo por CG-EM/ Application of the matrix solid phase dispersion (MSPD) technique in the analysis of pesticides in okra by GC-MS

Dórea, Haroldo Silveira; Lopes, Waneide Gomes
2004-12-01

Resumo em inglês A matrix solid phase dispersion and gas chromatography-mass selective detection method for the simultaneous determination of monocrotophos, methyl parathion, cypermethrin and deltamethrin in okra is described. Analyses of 2 g of fortified okra (0.05-0.75 mg kg-1) showed an average recovery of 96.2% (71.4-128.4%) and average relative standard deviation of 11.7% (1.4-37.1%). The cypermethrin recovery at the lower level was above 130%. The limit of detection ranged from 0.02 (mais) to 0.15 mg kg-1. The procedure was applied to the okra samples and has found 0.56 mg kg-1 of cypermethrin-cis, 0.75 mg kg-1 of cypermethrin-trans and 2.71 mg kg-1 of deltamethrin.

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97

Aplicação da cromatografia por exclusão e da cromatografia gasosa de alta resolução na análise do café/ Application of exclusion chromatography and high resolution gas chromatography to coffee analysis

Moreira, R. F. A.; Trugo, L. C.; Maria, C. A. B. de
1997-02-01

Resumo em inglês The combination of high performance exclusion chromatography (HPEC) and gas chromatography (GC) was applied to the analysis of six coffee samples that were previously characterized by sensory tests as of good or poor quality. The data obtained by the two techniques were statistically evaluated by "Principal Components Analysis" (PCA) using selected peak areas. The results showed the potential of the described techniques for coffee analysis. The HPEC technique monitored wi (mais) th the U.V. detector at 272 nm and followed by PCA may be correlated with sensorial data, particularly if a wider group of samples is used.

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98

Análise por cromatografia gasosa de BTEX nas emissões de motor de combustão interna alimentado com diesel e mistura diesel-biodiesel (B10)/ Analysis of BTEX in the emissions from an internal combustion engine burning diesel oil and diesel-biodiesel mixture (B10) by gas chromatography

Ferreira, Sérgio L.; Santos, Antônio M. dos; Souza, Gustavo R. de; Polito, Wagner L.; Módolo, Délson L.
2008-01-01

Resumo em inglês This paper describes the procedures for analysing pollutant gases emitted by engines, such as volatile organic compounds (benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene) by using high resolution gas chromatography (HRGC). For IC engine burning, in a broad sense, the use of the B10 mixture reduces drastically the emissions of aromatic compounds. Especially for benzene the reduction of concentrations occurs at the level of about 24.5%. Although a concentrat (mais) ion value below 1 µg mL-1 has been obtained, this reduction is extremely significant since benzene is a carcinogenic compound.

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99

Análise macroscópica infra-vermelha da difusão do óxido nitroso via inalatória para a cavidade abdominal, em ratos submetidos a pneumoperitônio/ Macroscopic infrared analysis of inhaled nitrous oxide diffusion to abdominal cavity in rats submitted to pneumoperitoneum/ Análisis macroscópica infrarroja de la difusión del óxido nitroso vía inhalatoria para la cavidad abdominal, en ratones sometidos a pneumoperitoneo

Colman, Daniel; Brioschi, Marcos Leal; Cimbalista Júnior, Mário; Tambara, Elizabeth Mila; Melo, Maria Célia Barbosa Fabrício de; Blume, Leonardo Pimpão
2004-04-01

Resumo em português JUSTIFICATIVA E OBJETIVOS: O óxido nitroso (N2O), por ser uma estrutura tri-atômica assimétrica, assume características de alta emissão e absorção de energia no espectro infra-vermelho, com um pico característico de absorção em 4,5 µm, o que o torna visível ao infra-vermelho curto, quando contrastado com uma fonte emissora de calor (anteparo quente). Diversos autores têm descrito a difusão do N2O para cavidades fechadas por métodos como cromatografia gasosa (mais) e analisador de gases, que não permitem um estudo macroscópico detalhado do gás. O presente estudo teve como objetivo a filmagem macroscópica no espectro infra-vermelho da difusão de N2O, utilizado em anestesia inalatória, para a cavidade peritoneal de ratos submetidos a pneumoperitônio de 20 mmHg com ar ambiente. MÉTODO: Dividiu-se os animais em três grupos, de acordo com o anestésico utilizado: I - controle venoso: tiopental intra-peritoneal; II - controle inalatório: isoflurano a 1,2% em O2 100%; III - óxido nitroso: N2O 66% em oxigênio e isoflurano a 0,6%. Os termogramas provenientes da descompressão abdominal foram obtidos, por meio de um radiômetro AGEMA 550 filmados a 7 quadros por segundo. RESULTADOS: O N2O demonstrou-se visível ao infra-vermelho. No momento da descompressão abdominal, não houve nos grupos I e II termogramas com rastros de gases visíveis ao infra-vermelho. Houve, porém, rastros de gases visíveis ao infra-vermelho no grupo III. CONCLUSÕES: Conclui-se que o óxido nitroso inalatório a 66% difundiu-se para a cavidade peritoneal de ratos submetidos a pneumoperitônio de 20 mmHg com ar ambiente, sem aumento de pressão intra-abdominal. Resumo em espanhol JUSTIFICATIVA Y OBJETIVOS: El óxido nitroso (N2O), por ser una estructura tri-atómica asimétrica, toma características de alta emisión y absorción de energía en el espectro infrarrojo, con un pico característico de absorción en 4,5 µm, lo que lo hace visible al infrarrojo corto, cuando contrastado con una fuente emisora de calor (resguardo caliente). Diversos autores han descrito la difusión del N2O para cavidades cerradas por métodos como cromatografia gaseos (mais) a y analizador de gases, que no permiten un estudio macroscópico detallado del gas. El presente estudio tubo como objetivo la filmación macroscópica en el espectro infrarrojo de la difusión de N2O, utilizado en anestesia inhalatoria, para la cavidad peritoneal de ratones sometidos a pneumoperitoneo de 20 mmHg con aire ambiente. MÉTODO: Los animales fueron divididos en tres grupos, de acuerdo con el anestésico utilizado: I- Control venoso: tiopental intra-peritoneal; II- Control inhalatorio: isoflurano a 1,2% en O2 100%; III- Óxido Nitroso: N2O 66% en oxígeno e isoflurano a 0,6%. Los termogramas provenientes de la descompresión abdominal fueron obtenidos, por medio de un radiómetro AGEMA 550 filmados a 7 cuadros por segundo. RESULTADOS: El N2O se demostró visible al infrarrojo. En el momento de la descompresión abdominal, no hubo en los grupos I y II termogramas con rastros de gases visibles al infrarrojo. Hubo, todavía, rastros de gases visibles al infrarrojo en el grupo III. CONCLUSIONES: Se concluye que el óxido nitroso inhalatorio a 66% se difundió para la cavidad peritoneal de ratones sometidos a pneumoperitoneo de 20 mmHg con aire ambiente, sin aumento de la presión intra-abdominal. Resumo em inglês BACKGROUND AND OBJECTIVES: Nitrous oxide (N2O), for its tri-atomic asymmetric structure, has high energy emission and absorption characteristics within the infrared spectrum, with maximum absorption at 4.5 µm, what makes it visible at short infrared, when contrasted with a heat emission source (hot support). Many authors have described N2O diffusion to closed cavities by chromatography methods and gas analyzers, which do not allow a detailed macroscopic study of the gas. (mais) This study aimed at macroscopically filming in the infrared spectrum inhaled N2O diffusion to the peritoneal cavity of rats submitted to 20 mmHg room air pneumoperitoneum. METHODS: Animals where divided in three groups according to the anesthetic drug: I - Intravenous control: intraperitoneal thiopental; II - inhaled control: 1.2% isoflurane in 100% O2; III - nitrous oxide: 66% N2O in oxygen and 0.6% isoflurane. Thermal images of abdominal decompression where captured by an AGEMA 550 radiometer filmed at 7 frames per second. RESULTS: N2O was visible to infrared. At abdominal decompression, groups I and II have not shown visible gas traces at infrared thermographs, while group III had visible infrared traces. CONCLUSIONS: Our conclusion was that 66% inhaled nitrous oxide has diffused to peritoneal cavity of rats submitted to 20 mmHg room air pneumoperitoneum, with no intra-abdominal pressure increase.

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Análise de ácidos graxos não-esterificados de plasma humano por cromatografia gasosa capilar com injeção sem divisão de fluxo/ Analysis of non-esterified fatty acids in human plasma by capillary gas-chromatography with splitless injection

Ney, Jacqueline G.; Torres, Alexandre G.; Trugo, Nádia M. F.
2004-08-01

Resumo em inglês The aim of the present work was to test the combination of non-esterified fatty acid (NEFA) isolation using fumed silicon dioxide with capillary gas-chromatography (C-GC) with splitless injection for the analysis of NEFAs in human plasma. Injection volume, solvent re-condensation and split purge flow-rate were the parameters evaluated for the analysis of fatty acid methyl esters by C-GC. The use of a solvent re-condensation technique, associated with 1.0 µL injection and (mais) a split purge flow rate of 80 mL/min resulted in satisfactory analysis of NEFAs. Fourteen fatty acids were identified in plasma samples, ranging from 2.03 to 184.0 µmol/L. The combination of both techniques proved useful for routine analyses of plasma NEFAs.

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101

Análise de resíduos de pesticidas em tomates por cromatografia em camada delgada/ Analysis of residue pesticide in tomatoes by thin layer chromatography

Moraes, Solange Leite; Rezende, Maria Olímpia Oliveira; Nakagawa, Lia Emi; Luchini, Luiz Carlos
2002-05-01

Resumo em inglês Pesticide residues are determined by thin layer chromatography (TLC) using the Hill reaction as a detection method. Tomatoes samples without pesticide were fortified with atrazine, diuron, chloroxuron and metribuzin, and were applyed in silica gel plates with the help of a microsyringe. The pesticides were elued with ethyl acetate. There was no need of cleaning up because no interference was noticed. After the revelation of the plates, the diameters of the spots were meas (mais) ure by using a rule. The range of the determined concentration for all the pesticides was from 0.1 to1.0 ng/muL. The results obtained through TLC can be used for semi-quantitative analysis.The results obtained were compared to gas and liquid chromatography, showing good agreement between both techniques.

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102

Acoplamento cromatografia gasosa - espectrometria de absorção atômica em estudos de especiação: uma revisão/ Gas chromatography coupled with atomic absorption spectrometry

Campos, Reinaldo Calixto de; Grinberg, Patricia
2001-04-01

Resumo em inglês This review presents an updated overview of the trace element speciation by gas chromatography coupled with atomic absorption spectrometry.

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103

Cromatografia unificada/ Unified chromatography

Mühlen, Carin von; Lanças, Fernando Mauro
2004-10-01

Resumo em inglês The scope of this study encompasses an overview of the principles of unified chromatography as well as the principles of chromatographic techniques as applied to unified systems, which include gas chromatography, liquid chromatography, supercritical fluid chromatography, high temperature and high pressure liquid chromatography, micro-liquid chromatography, enhanced fluidity chromatography, and solvating gas chromatography. Theoretical considerations and individual instrum (mais) ental parameters such as mobile phase, sample introduction system, columns, and detection system are also discussed. Future applications of this separation approach are discussed.

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104

Cromatografia gasosa ultrarrápida: uma visão geral sobre parâmetros, instrumentação e aplicações/ Ultra fast gas chromatography: an overview of the main parameters, instrumentation and applications

Sequinel, Rodrigo; Hatanaka, Rafael Rodrigues; Gualtieri, Carlos Eduardo; Flumignan, Danilo Luiz; Oliveira, José Eduardo de; Passaretti Filho, Juliano
2010-01-01

Resumo em inglês Since the introduction of GC there has been an ongoing interest in reducing time of analysis resulting in new terms and definitions such as ultra fast gas chromatography (UF-GC). One of the most used definitions describes UF-GC as a technique that combines the employment of short narrow bore column with very fast temperature programming rates producing chromatographic peaks in the range of 50 ms and allowing separations times in 1-2 min or less. This paper summarizes the analytical approaches, the main parameters involved and the instrumentation towards UF-GC.

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105

Cromatografia gasosa bidimensional abrangente (GC × GC)/ Comprehensive two-dimensional gas chromatography (GC × GC)

Pedroso, Marcio Pozzobon; Godoy, Luiz Antonio Fonseca de; Fidélis, Carlos Henrique de Vasconcellos; Ferreira, Ernesto Correa; Poppi, Ronei Jesus; Augusto, Fabio
2009-01-01

Resumo em inglês This paper presents the fundamental principles, instrumentation and selected applications of comprehensive two-dimensional gas chromatography (GC × GC). In this technique, introduced in 1991, two capillary columns are coupled and proper modulating interfaces continuously collect the eluate from the first column, transferring it to the second column. The result is a geometric increment in the chromatographic resolution, ensuring separation of extremely complex mixture (mais) s in time periods shorter or comparable to those of analysis using conventional gas chromatography and with better detectabilities and sensitivities.

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