The BIOREMA project – part 3: International interlaboratory comparison for bio-ethanol test methods

Published

January 1, 2012

Author(s)

Michele M. Schantz, Adriaan van der Veen, Hugo Ent, Annaratia Baldan, Valnei Cunha, Romeu Daroda, Manuela Ulberth-Buchgraber, Brian E. Lang, Andrea Held, Ruth Hearn, Richard Brown, Paul Brewer

Abstract

The main objective of the BIOREMA (Reference Materials for Biofuel Specifications) project is the development of two test materials (one bio-ethanol material and one biodiesel material) with well-established reference values. This paper describes the material preparation, homogeneity study, stability study, and characterisation of the bio–ethanol material. The test material obtained was used in an interlaboratory comparison (ILC) to assess current practices and comparability among analytical laboratories providing bio–ethanol testing services. The ILC compared measurement results from testing laboratories with reference values for the bio-ethanol material obtained during this project. The emphasis was on recognising and interpreting systematic differences between pre-assigned values and laboratory results. Only 13 participants provided data, resulting in a small data set for evaluation. Further, it appeared that for a number of laboratories there was not sufficient material for the determination of all requested parameters. In most cases, as far as the data permit, it can be concluded that the consensus values (based on participant’s results) are in good agreement with the reference or the BIOREMA values (obtained by the NMIs participating in the project). For three parameters, namely ethanol, water content and density, there is good agreement between the reference and consensus values. For these parameters, the reproducibility standard deviation is close to, or even smaller than, the expanded uncertainty associated with the reference value. A number of parameters show very poor reproducibility, e.g. pHe, electrolytic conductivity, and acidity. The same applies to sodium and copper content, which are very low and therefore challenging parameters to measure accurately. The results of the ILC underpin the need for certified reference materials, and demonstrate the requirement for more robust quality control to improve the precision and trueness of the results fr

Citation

Accreditation and Quality Assurance

Volume

18

Pub Type

Journals

Keywords

BIOREMA, bioethanol, interlaboratory comparison, biofuel

Citation

Schantz, M. , van, A. , Ent, H. , Baldan, A. , Cunha, V. , Daroda, R. , Ulberth-Buchgraber, M. , Lang, B. , Held, A. , Hearn, R. , Brown, R. and Brewer, P. (2012), The BIOREMA project – part 3: International interlaboratory comparison for bio-ethanol test methods, Accreditation and Quality Assurance (Accessed May 5, 2024)