pH Measurement in Bioethanol by Using Different Electrodes and according to International Standards

    Volume 7, Issue 4 (April 2010)

    ISSN: 1546-962X

    CODEN: JAIOAD

    Published Online: 1 April 2010

    Page Count: 6


    Borges, P. P.
    National Institute of Metrology, Normalization and Industrial Quality—Inmetro Directorate of Scientific and Industrial Metrology–Dimci Chemical Metrology Div.—Dquim Electrochemistry Laboratory—Label Av. Nossa Senhora da Graças 50, Duque de Caxias, RJ

    Fraga, I. C. S.
    National Institute of Metrology, Normalization and Industrial Quality—Inmetro Directorate of Scientific and Industrial Metrology–Dimci Chemical Metrology Div.—Dquim Electrochemistry Laboratory—Label Av. Nossa Senhora da Graças 50, Duque de Caxias, RJ

    Marques, B. S. R.
    National Institute of Metrology, Normalization and Industrial Quality—Inmetro Directorate of Scientific and Industrial Metrology–Dimci Chemical Metrology Div.—Dquim Electrochemistry Laboratory—Label Av. Nossa Senhora da Graças 50, Duque de Caxias, RJ

    Dias, J. C.
    National Institute of Metrology, Normalization and Industrial Quality—Inmetro Directorate of Scientific and Industrial Metrology–Dimci Chemical Metrology Div.—Dquim Electrochemistry Laboratory—Label Av. Nossa Senhora da Graças 50, Duque de Caxias, RJ

    Cunha, V. S.
    National Institute of Metrology, Normalization and Industrial Quality—Inmetro Directorate of Scientific and Industrial Metrology–Dimci Chemical Metrology Div.—Dquim Electrochemistry Laboratory—Label Av. Nossa Senhora da Graças 50, Duque de Caxias, RJ

    (Received 30 May 2009; accepted 12 February 2010)

    Abstract

    The importance of Brazilian bioethanol as biofuel has been increasing significantly. Its origin from renewable sugar cane is able to reduce carbon in the atmosphere and is one of the factors that contribute for reducing global warming. Because of the difficulty in measuring pH in nonaqueous solutions, Inmetro, the Brazilian Metrology Institute, has focused its attention on the needs for accurate and reliable pH measurements, as part of its work in developing and producing certified reference material (CRM) of bioethanol. This paper aims to present the studies of pH measurement in CRM of bioethanol from sugar cane (approximately 99.6 % ethanol content) using two commercial pH electrodes with different internal filling electrolytic solutions. One electrode, containing potassium chloride (KCl), was specified in the American standard, ASTM D6423, and the other one, containing lithium chloride (LiCl), was specified in the Brazilian standard, ABNT NBR 10891, and European standard EN 15490. These studies have shown that there was a significant difference among the pH values (more than 1.0 pH unit) measured by the different electrodes related to its internal filling solution. The results have shown that a harmonization of the standardization on the pH measurement is needed in order to make possible its use and application as analytical parameter.


    Paper ID: JAI102588

    DOI: 10.1520/JAI102588

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    Author
    Title pH Measurement in Bioethanol by Using Different Electrodes and according to International Standards
    Symposium , 0000-00-00
    Committee D02