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Dive into the research topics where M. A. Barbirato is active.

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Featured researches published by M. A. Barbirato.


Chromatographia | 1994

Supercritical fluid extraction of oxadixyl from food crops

Fernando M. Lanças; M. S. Galhiane; M. A. Barbirato

SummaryThis work describes the study of a degradation curve of Oxadixyl in field-treated potato and tomato samples. The residues were extracted using classical and supercritical fluid (SFE) extraction methods and analyzed by HRGC/ECD. The extraction techniques were compared and the results indicate the advantages of using SFE as an alternative method for pesticide analyses in these samples.


Chromatographia | 1995

Extraction of norflurazon residues in cotton seeds with supercritical CO2

Fernando M. Lanças; M. A. Barbirato; M. S. Galhiane

SummaryA new method for the extraction of Norflurazon residues in cotton seeds using supercritical CO2 as the extracting fluid is described. The supercritical fluid extraction results were compared with those of the classical procedure using liquid extraction. All SFE experiments were performed using a home-made system. The method presented, besides being faster and more economical than existing methods, showed better recovery, with higher selectivity for Norflurazon extraction.


Chromatographia | 2000

Profiling Propolis Flavonoids by Means of Micellar Electrokinetic Capillary Chromatography, Capillary Gas Chromatography and Bactericidal Action

José D. Fontana; Maurício Passos; M. H. R. dos Santos; C. K. Fontana; Bruno Oliveira; L. Schause; Roberto Pontarolo; M. A. Barbirato; M. A. Ruggiero; Fernando M. Lanças

SummaryThere is no proportional correlation between increasing organic solvent polarity from hexane to methanol and the extractability of propolis solids by the solvents or the bactericidal action of the propolis extracts obtained. Hexane (17.7%) and chloroform (62.1%) were the poorest and the best extractants, respectively, for propolis solids. The antibiotic activity of the extracts againstStaphylococcus strains decreased in the order hexane≥ethanol>methanol. Different capillary GC profiles were obtained for persilyl derivatives of propolis extracted with hexane and methanol and for propolis collected in different Brazilian provinces, suggesting the influence of flora variability on propolis composition. Wavelength-selected DAD detection revealed MEKC to be an innovative and sensitive method for monitoring the occurrence in propolis of the flavonoids and phenolcarboxylic acids thought to be responsible for the antimicrobial activity of propolis.


Chromatographia | 1996

Supercritical fluid extraction of chlorothalonil residues from apples

Fernando M. Lanças; M. A. Barbirato; M. S. Galhiane; Sandra R. Rissato

SummaryA new method for the extraction of Chlorothalonil residues from apples using supercritical CO2 as the extracting fluid is described. The supercritical fluid extraction results were compared with those obtained by solid-liquid extraction. The results showed that SFE is faster and more selective with better recovery and higher selectivity.


Chromatographia | 1996

Simultaneous extraction of norflurazon and oxadixyl residues from food crops with supercritical carbon dioxide

Fernando M. Lanças; M. A. Barbirato; M. S. Galhiane

SummaryNorflurazon and Oxadixyl residues have been analysed by HRGC-ECD after extraction from field-treated sugar cane and grapes using classical solid-liquid extraction or supercritical fluid extraction. The extraction techniques were compared; the results indicate the advantages of SFE as an alternative method for analysis of pesticides in these samples.


Chromatographia | 1996

Extraction of Atabron residues from cabbage with supercritical carbon dioxide

Fernando M. Lanças; M. A. Barbirato; M. S. Galhiane

SummaryIn this work we present a new procedure for extraction of Atabron residues from cabbage samples using supercritical carbon dioxide. The results obtained with this procedure were compared with those obtained using traditional extraction methods for Atabron residues. The extraction yields found by both procedures are similar but SFE has several advantages, especially higher speed, greater economy, better selectivity and greater reproducibility.


Petroleum Science and Technology | 1994

CHROMATOGRAPHIC ISOLATION OF NITROGEN-CONTAINING COMPOUNDS IN LIQUID FUELS 1 Ti(IV) OXIDE GRAFTED ONTO SILICA AS STATIONARY PHASE

Fernando M. Lanças; M. A. Barbirato

Abstract The present work describes a novel method for the isolation of the neutral N-containing fraction from crude oil using column liquid chromatography on silica gel chemically modified with Ti(IV) oxide using a grafting method. The crude oil sample is introduced onto the column and eluted with a proper sequence of eluents. The first eluted fraction contains only hydrocarbons. The N-containing compounds are eluted in a isolated fraction. Both fractions are collected, concentrated and analyzed using HRGC with NPD detection. The method is shown to be very selective for the isolation of the neutral N-containing fractions from crude oil.


Petroleum Science and Technology | 1994

CHROMATOGRAPHIC ISOLATION OF NITROGEN - CONTAINING COMPOUNDS IN LIQUID FUELS 2. THERMALLY TREATED SILICA GEL AS STATIONARY PHASE

Fernando M. Lanças; M. A. Barbirato

Abstract In the present work we describe a novel method for the isolation of the neutral N-containing fraction from crude oil by preparative liquid chromatography using thermally treated silica gel as stationary phase. The hydrocarbons are eluted in the first two fractions and the nitrogen compounds in the third fraction. The collected fractions are analyzed by HRGC-NPD. The method is shown to be very selective for the isolation of nitrogen compounds from the neutral fractions of crude oil.


Food Science and Technology International | 1997

NOVAS APLICAÇÕES DE SISTEMAS DE PARA EXTRAÇÃO COM FLUIDO SUPERCRÍTICO (SFE)" HOME-MADE".: VI. CONTROLE DE AGROTÓXICOS EM PRODUTOS ALIMENTÍCIOS

Fernando M. Lanças; M. A. Barbirato; M. S. Galhiane; Sandra R. Rissato

In the present work, we describe a SFE home-made system used for pesticide residue extraction in food products. The pesticides were extracted using CO2 in the supercritical state as extracting fluid with and without modifiers. The results obtained by SFE have been better than those obtained by conventional extraction method.


Hrc-journal of High Resolution Chromatography | 1997

Effect of temperature, collection mode, and modifier on the supercritical CO2 extraction of dicofol residues from fish samples

Fernando M. Lanças; Mario Sergio Galhiane; Sandra Regina Rissato; M. A. Barbirato

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M. S. Galhiane

University of São Paulo

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Bruno Oliveira

Federal University of Paraná

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Haroldo Silveira Dórea

Universidade Federal de Sergipe

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José D. Fontana

Federal University of Paraná

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M. A. Ruggiero

University of São Paulo

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M. H. R. dos Santos

Federal University of Paraná

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Maurício Passos

Federal University of Paraná

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Roberto Pontarolo

Federal University of Paraná

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