Journal Published Online: 21 December 2009
Volume 7, Issue 2

Water Content Determination in Biodiesel: Optimization of Methodology in Coulometric Karl Fischer Titration

CODEN: JAIOAD

Abstract

Coulometric Karl Fischer (KF) titration is a highly accurate technique employed for moisture determination in non-aqueous solvents. Methodology for coulometric titration in a KF apparatus coupled to an autosampler oven was optimized in order to improve the accuracy of moisture determination in biodiesel derived from soybean. Several parameters were investigated, and three of them were optimized according to a central composite 23 star experimental design. The highest accuracy for moisture determinations corresponded to a relative standard deviation of 1.48 %. It was reached when the KF titrator was operated with electrode without diaphragm, the sample mass was 4 g, and the oven temperature was set to 170°C. Other parameters, like carrier gas flux and extraction time, presented minimal or no effects for improving the accuracy of moisture determination.

Author Information

Vicentim, M.
Laboratório de Análise Orgânica, Divisão de Metrologia Química, DIMCI/INMETRO, 50 Prédio 6, Xerém, Duque de Caxias, Rio de Janeiro, Brazil
Barreto Sousa, M.
Laboratório de Análise Orgânica, Divisão de Metrologia Química, DIMCI/INMETRO, 50 Prédio 6, Xerém, Duque de Caxias, Rio de Janeiro, Brazil
Fernandes da Silva, V.
Laboratório de Análise Orgânica, Divisão de Metrologia Química, DIMCI/INMETRO, 50 Prédio 6, Xerém, Duque de Caxias, Rio de Janeiro, Brazil
Mateus, V.
Laboratório de Análise Orgânica, Divisão de Metrologia Química, DIMCI/INMETRO, 50 Prédio 6, Xerém, Duque de Caxias, Rio de Janeiro, Brazil
Rodrigues, J.
Laboratório de Análise Orgânica, Divisão de Metrologia Química, DIMCI/INMETRO, 50 Prédio 6, Xerém, Duque de Caxias, Rio de Janeiro, Brazil
Smarçaro da Cunha, V.
Laboratório de Análise Orgânica, Divisão de Metrologia Química, DIMCI/INMETRO, 50 Prédio 6, Xerém, Duque de Caxias, Rio de Janeiro, Brazil
Pages: 7
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Stock #: JAI102615
ISSN: 1546-962X
DOI: 10.1520/JAI102615