Development of a fast capillary electrophoresis method to determine inorganic cations in biodiesel samples

The aim of this study was to develop a fast capillary electrophoresis method for the determination of inorganic cations (Na(+), K(+), Ca(2+), Mg(2+)) in biodiesel samples, using barium (Ba(2+)) as the internal standard. The running electrolyte was optimized through effective mobility curves in order to select the co-ion and Peakmaster software was used to determine electromigration dispersion and buffer capacity. The optimum background electrolyte was composed of 10 mmol L(-1) imidazole and 40 mmol L(-1) of acetic acid. Separation was conducted in a fused-silica capillary (32 cm total length and 23.5 cm effective length, 50 mu m I.D.), with indirect UV detection at 214 nm. The migration time was only 36 s. In order to obtain the optimized conditions for extraction, a fractional factorial experimental design was used. The variables investigated were biodiesel mass, pH, extractant volume, agitation and sonication time. The optimum conditions were: biodiesel mass of 200 mg, extractant volume of 200 mu L. and agitation of 20 min. The method is characterized by good linearity in the concentration range of 0.5-20 mg kg(-1) (r > 0.999), limit of detection was equal to 0.3 mg kg(-1), inter-day precision was equal to 1.88% and recovery in the range of 88.0-120%. The developed method was successfully applied to the determination of cations in biodiesel samples. (c) 2010 Elsevier B.V. All rights reserved.

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Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)[576230/2008-1]

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)[473689/2007-3]

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)[476386/2007-1]

Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)[130820/2008-3]

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)[300593/2008-2]

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fundacao de Amparo a Pesquisa do Estado de Santa Catarina (FAPESC)

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Fundacao de Amparo a Pesquisa do Estado de Minas Gerais of Brazil (FAPEMIG)

Fundacao de Amparo a Pesquisa do Estado de Minas Gerais of Brazil (FAPEMIG)[CEX-APQ 1906-502/07]

Fundacao de Amparo a Pesquisa do Estado de Minas Gerais of Brazil (FAPEMIG)[CEX APQ 01837/08]

Fundacao de Amparo a Pesquisa do Estado de Minas Gerais of Brazil (FAPEMIG)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)

Farma Service Bioextract

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