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Sensors 2010, 10(11), 9982-9993;

Sensitivities of a Standard Test Method for the Determination of the pHe of Bioethanol and Suggestions for Improvement

Analytical Science Team, National Physical Laboratory, Teddington, Middlesex, TW110LW, UK
School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
Author to whom correspondence should be addressed.
Received: 19 September 2010 / Revised: 22 October 2010 / Accepted: 25 October 2010 / Published: 9 November 2010
(This article belongs to the Section Chemical Sensors)
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An assessment of the sensitivities of the critical parameters in the ASTM D6423 documentary standard method for the measurement of pHe in (bio)ethanol has been undertaken. Repeatability of measurements made using the same glass electrode and reproducibility between different glass electrodes have been identified as the main contributors to the uncertainty of the values produced. Strategies to reduce the uncertainty of the measurement have been identified and tested. Both increasing the time after which the pHe measurement is made following immersion in the sample, and rinsing the glass electrode with ethanol prior to immersion in the sample, have been shown to be effective in reducing the uncertainty of the numerical value produced. However, it is acknowledged that the values produced using these modified approaches may not be directly compared with those obtained using the documentary ASTM method since pHe is defined operationally by the process used to measure it. View Full-Text
Keywords: pHe; ethanol; biofuels; uncertainty; standard methods pHe; ethanol; biofuels; uncertainty; standard methods

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This is an open access article distributed under the Creative Commons Attribution License (CC BY 3.0).

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Brown, R.J.C.; Keates, A.C.; Brewer, P.J. Sensitivities of a Standard Test Method for the Determination of the pHe of Bioethanol and Suggestions for Improvement. Sensors 2010, 10, 9982-9993.

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