Treatment of bimodality in proficiency test of pH in bioethanol matrix

Verfasser / Beitragende:
[Gabriel Sarmanho, Paulo Borges, Isabel Fraga, Luiz Leal]
Ort, Verlag, Jahr:
2015
Enthalten in:
Accreditation and Quality Assurance, 20/3(2015-06-01), 179-187
Format:
Artikel (online)
ID: 605465789
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024 7 0 |a 10.1007/s00769-015-1133-4  |2 doi 
035 |a (NATIONALLICENCE)springer-10.1007/s00769-015-1133-4 
245 0 0 |a Treatment of bimodality in proficiency test of pH in bioethanol matrix  |h [Elektronische Daten]  |c [Gabriel Sarmanho, Paulo Borges, Isabel Fraga, Luiz Leal] 
520 3 |a The pH value in bioethanol is a quality control parameter related to its acidity and to the corrosiveness of vehicle engines when it is used as fuel. In order to verify the comparability and reliability of the measurement of pH in bioethanol matrix among some experienced chemical laboratories, reference material of bioethanol developed by Inmetro—the Brazilian National Metrology Institute—was used in a proficiency testing (PT) scheme. There was a difference of more than one unit in the value of the pH measured due to the type of internal filling electrolytic solutions (potassium chloride, KCl, or lithium chloride, LiCl) from the commercial pH combination electrodes used by the participant laboratories. Therefore, bimodal distribution has occurred from the data of this PT scheme. This work aimed to present the possibilities that a PT scheme provider can use to overcome the bimodality problem. Data from the PT of pH in bioethanol were treated by two different statistical approaches: kernel density model and the mixture of distributions. Application of these statistical treatments improved the initial diagnoses of PT provider, by solving bimodality problem and contributing for a better performance evaluation in measuring pH of bioethanol. 
540 |a Springer-Verlag Berlin Heidelberg, 2015 
690 7 |a Bioethanol  |2 nationallicence 
690 7 |a pH  |2 nationallicence 
690 7 |a Proficiency test  |2 nationallicence 
690 7 |a Multimodality  |2 nationallicence 
690 7 |a Kernel density  |2 nationallicence 
690 7 |a Mixture of densities  |2 nationallicence 
700 1 |a Sarmanho  |D Gabriel  |u Chemical Metrology Division (Dquim), National Institute of Metrology, Quality and Technology (Inmetro), Av. Nossa Senhora das Graças, 50, 25250-020, Xerém, Rio de Janeiro, Brazil  |4 aut 
700 1 |a Borges  |D Paulo  |u Chemical Metrology Division (Dquim), National Institute of Metrology, Quality and Technology (Inmetro), Av. Nossa Senhora das Graças, 50, 25250-020, Xerém, Rio de Janeiro, Brazil  |4 aut 
700 1 |a Fraga  |D Isabel  |u Chemical Metrology Division (Dquim), National Institute of Metrology, Quality and Technology (Inmetro), Av. Nossa Senhora das Graças, 50, 25250-020, Xerém, Rio de Janeiro, Brazil  |4 aut 
700 1 |a Leal  |D Luiz  |u Corporate Management Division (Dgcor), National Institute of Metrology, Quality and Technology (Inmetro), R. Santa Alexandrina, 416, 20261-232, Rio Comprido, Rio de Janeiro, Brazil  |4 aut 
773 0 |t Accreditation and Quality Assurance  |d Springer Berlin Heidelberg  |g 20/3(2015-06-01), 179-187  |x 0949-1775  |q 20:3<179  |1 2015  |2 20  |o 769 
856 4 0 |u https://doi.org/10.1007/s00769-015-1133-4  |q text/html  |z Onlinezugriff via DOI 
898 |a BK010053  |b XK010053  |c XK010000 
900 7 |a Metadata rights reserved  |b Springer special CC-BY-NC licence  |2 nationallicence 
908 |D 1  |a research-article  |2 jats 
949 |B NATIONALLICENCE  |F NATIONALLICENCE  |b NL-springer 
950 |B NATIONALLICENCE  |P 856  |E 40  |u https://doi.org/10.1007/s00769-015-1133-4  |q text/html  |z Onlinezugriff via DOI 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Sarmanho  |D Gabriel  |u Chemical Metrology Division (Dquim), National Institute of Metrology, Quality and Technology (Inmetro), Av. Nossa Senhora das Graças, 50, 25250-020, Xerém, Rio de Janeiro, Brazil  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Borges  |D Paulo  |u Chemical Metrology Division (Dquim), National Institute of Metrology, Quality and Technology (Inmetro), Av. Nossa Senhora das Graças, 50, 25250-020, Xerém, Rio de Janeiro, Brazil  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Fraga  |D Isabel  |u Chemical Metrology Division (Dquim), National Institute of Metrology, Quality and Technology (Inmetro), Av. Nossa Senhora das Graças, 50, 25250-020, Xerém, Rio de Janeiro, Brazil  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Leal  |D Luiz  |u Corporate Management Division (Dgcor), National Institute of Metrology, Quality and Technology (Inmetro), R. Santa Alexandrina, 416, 20261-232, Rio Comprido, Rio de Janeiro, Brazil  |4 aut 
950 |B NATIONALLICENCE  |P 773  |E 0-  |t Accreditation and Quality Assurance  |d Springer Berlin Heidelberg  |g 20/3(2015-06-01), 179-187  |x 0949-1775  |q 20:3<179  |1 2015  |2 20  |o 769