title: Certified reference material of bioethanol for metrological traceability in electrochemical parameters analyses.
abstract: Bioethanol has become an important biofuel because it is a source of renewable energy and can help to decrease global warming. However, the quality of bioethanol needs to be guaranteed so that it can be trusted and accepted in international trade. The Brazilian Metrology Institute (Inmetro) has been developing a certified reference material (CRM) for bioethanol to ensure quality control for measurement in the bioethanol matrix. Inmetro has certified 11 quality parameters. Using these, the CRM of bioethanol will contribute to guaranteeing metrological traceability and reliable measurement results. These factors can be used to compare different bioethanols produced to comply with legislation in different countries in order to avoid technical barriers and thus increase the international trade in Brazilian bioethanol. The aim of this paper is to present the results of certification studies using three important electrochemical quality parameters in the CRM of bioethanol-total acid number, pHe and electrolytic conductivity-which are crucial in protecting the metallic parts of a vehicle from corrosion. The certified results obtained for total acid number, pHe and electrolytic conductivity parameters were (16.2±1.7)mg L(-1), 6.07±0.30, and (1.03±0.11)μS cm(-1), respectively. The uncertainties for all parameters were the expanded uncertainty obtained by multiplying the combined standard uncertainty by a coverage factor of k=2, which represents an approximately 95% confidence level.
authors.affiliation: National Institute of Metrology, Quality and Technology-Inmetro Chemical Metrology Division-Dquim, Electrochemistry Laboratory-Label Av. Nossa Senhora da Graças 50, Prédio 4, 25250-020 Xerém, Duque de Caxias, Rio de Janeiro, Brazil. icfraga@inmetro.gov.br
authors.forename: Isabel Cristina
authors.initials: IC
authors.lastname: Serta Fraga
authors.forename: Carla Matos
authors.initials: CM
authors.lastname: Ribeiro
authors.forename: Sidney Pereira
authors.initials: SP
authors.lastname: Sobral
authors.forename: Júlio Cesar
authors.initials: JC
authors.lastname: Dias
authors.forename: Mary Ane
authors.initials: MA
authors.lastname: Gonçalves
authors.forename: Paulo Paschoal
authors.initials: PP
authors.lastname: Borges
authors.forename: Fabiano Barbieri
authors.initials: FB
authors.lastname: Gonzaga
mesh_terms: D056804:Biofuels / Q000032:analysis*; D002568:Certification; D004563:Electrochemistry / Q000592:standards*; D000431:Ethanol / Q000032:analysis* / Q000737:chemistry*; D011786:Quality Control; D012015:Reference Standards
chemical_list: D056804:Biofuels; D000431:Ethanol