IMEKO Event Proceedings

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Paulo Paschoal Borges, Isabel Cristina S. Fraga, Bianca de Souza R. Marques, Júlio C. Dias, Sidney Pereira Sobral, Wiler Batista da S. Junior, Carla de M. Ribeiro, Jéssica C. Lopes, Valnei S. Cunha
pH MEASUREMENT CAPABILITY THROUGH THE PRIMARY pH MEASUREMENT OF CARBONATE BUFFER SOLUTION
The Chemical Metrology Division (Dquim) from National Institute of Metrology, Standardization and Industrial Quality - Inmetro established in 2003 the primary system of pH measurement. The main use of this system is to provide reliability and traceability to the pH measurements in Brazil since its measurement is one of the most important analyses carried out in many laboratories all over the country. In order to show comparability and capability in primary pH measurement, Inmetro participated in both the key-comparisons CCQM-K18 and in the supplementary comparison that followed, named CCQM-K18.1, to measure the pH in a carbonate buffer solution of nominal value of pH 10. Both exercises were organized by Consultative Committee for Amount of Substance (CCQM) of the International Bureau of Weights and Measures (BIPM). This work aimed at showing the development and optimization of the primary pH system from Inmetro in order to participate in the supplementary key-comparison. Inmetro´s results in that supplementary comparison have shown its capability in primary measurement of pH 10.
1st IMEKO TC24 Conference (MEFNM 2008 - together with TC19 and TC23), Budapest, HUNGARY, 2008

Isabel Cristina S. Fraga, Paulo Roberto G. Couto, Paulo Paschoal Borges, Bianca de Souza R. Marques, Wiler Batista da S. Junior, Carla de M. Ribeiro, Jéssica C. Lopes, Sidney Pereira Sobral, Júlio C. Dias, Valnei S. Cun
UNCERTAINTY BUDGET FOR PRIMARY ELECTROLYTIC CONDUCTIVITY MEASUREMENT COMPARING DIFFERENT METHODS
In 2007, the Chemical Metrology Division (Dquim) from National Institute of Metrology, Standardization and Industrial Quality - Inmetro, established the primary system of electrolytic conductivity (EC) measurement. The main use of this system is to provide reliability and traceability to the EC measurements in Brazil since its measurement is very important, mainly for determining the purity of water. In order to show comparability and capability in primary EC measurement, Inmetro has participated in the key-comparison organized by Consultative Committee for Amount of Substance (CCQM) called CCQM-K36.1 to measure the EC in two solutions: one with a nominal value of 0.5 S m^-1 and the other, 5 mS m^-1. This work aims to present a comparison among the values of the uncertainty results from primary EC measurement in the solution of 0.5 S m^-1 obtained by using the methods of ISO GUM, Kragten and Monte Carlo simulation. In addition, this work will also present an evaluation of the uncertainty related to all relevant sources in the uncertainty budget for EC measurement by using the primary EC system from Inmetro. Moreover, this study intends to show the main points which should be focused on in order to improve the process of primary EC measurement, when needed.
1st IMEKO TC24 Conference (MEFNM 2008 - together with TC19 and TC23), Budapest, HUNGARY, 2008

Rodrigo Vivarelli Poggi Leal, Paulo Paschoal Borges, Peter Rudolf Seidl
METROLOGICAL EVALUATION OF TITRATION TECHNIQUES FOR THE DETERMINATION OF THE IODINE VALUE IN BIODIESEL
Based on international standard procedures, the degree of unsaturation on biodiesel was evaluated, called iodine value. Two titration techniques were used to determine the iodine value: colorimetric and potentiometric techniques. The uncertainty of measurement was used to evaluate the quality of the results. The potentiometric technique showed better quality in the determination of the iodine value because of its accuracy as well as lower uncertainty result of the measurements, with values between 0,613 g I₂ / 100 g and 1,438 g I₂ / 100 g), compared to the results from the colorimetric technique, with values between 1,61 g I₂ / 100 g and 3,30 g I₂ / 100 g.
1st IMEKO TC24 Conference (MEFNM 2008 - together with TC19 and TC23), Budapest, HUNGARY, 2008

Margarida Maria Correia dos Santos, Sheila Alves, Maria Ascensão Trancoso
EVALUATION OF MEASUREMENT UNCERTAINTY OF METALS IN SOILS
Estimation of measurement uncertainty of the metal content in different soils was done using validation and quality control data. Precision under within-laboratory reproducibility conditions was estimated from duplicate analysis. Trueness was determined as recovery of the analyte from two certified reference materials (CRM). The CRM properties on the results obtained is critically evaluated.
1st IMEKO TC24 Conference (MEFNM 2008 - together with TC19 and TC23), Budapest, HUNGARY, 2008

Paola Fisicaro, Sébastien Sannac, Guillaume Labarraque, Florence Pannier, Martine Potin-Gautier
DEVELOPMENT OF A REFERENCE PROCEDURE FOR THE DETERMINATION OF METHYLMERCURY IN FISH PRODUCTS
The purpose of this work is to present the development of an analytical procedure for the speciation analysis of methylmercury in fish products. The paper is focused on the extraction of the sample, considered as one of the most difficult step in the speciation process, for which quantitative recovery and preservation of the integrity of the species should be considered.
1st IMEKO TC24 Conference (MEFNM 2008 - together with TC19 and TC23), Budapest, HUNGARY, 2008

Yiu-chung Wong, Tat-ting Kam, Serena Chan
DEVELOPMENT OF REFERENCE MATERIAL FOR ORGANOCHLORINE PESTICIDES IN HERBAL SAMPLE
Development of reference material for hexachlorobenzene and three isomers of hexachlorocyclohexane in ginseng root sample to assure the quality control of organochlorine analysis was presented. The assigned values of the reference material were determined using an accurate isotope dilution gas chromatography-mass spectrometry technique.
1st IMEKO TC24 Conference (MEFNM 2008 - together with TC19 and TC23), Budapest, HUNGARY, 2008

Melina Pérez Urquiza, Yoshito Mitani, Hector Nava Jaimes
USE OF REFERENCE VALUES FOR A PROFICIENCY TEST SCHEME IN THE MEASUREMENT OF GLUCOSE AND CHOLESTEROL IN HUMAN SERUM TO EVALUATE IVD KITS
The first proficiency testing round 630-IL-1002, was carried out with a Reference Material DMR-180a with reference values obtained by using Gas Chromatography Isotopic Dilution mass spectrometry (GC-IDMS) methods, in which glucose, cholesterol and creatinine were measured. The serum pool was obtained from blood donors and all the analytes were at the normal concentration in Mexican population. The laboratories participants used different field methods to measure the analytes. The Mexican compulsory standard NOM-064-SSA1-1993 "specifications for equipments IVD" requests <5% for reproducibility and accuracy of IVD equipments. The results obtained by field laboratories in the proficiency testing round are compared to the reference value and uncertainty provided by National Metrology Institute (CENAM). The quality of measurements are dependent not only on the laboratory competence but also on the methods used by those commercially available IVD kits. It is concluded that quality assessment of measurements in clinical laboratories should be critically evaluated by using stable and certified reference materials.
1st IMEKO TC24 Conference (MEFNM 2008 - together with TC19 and TC23), Budapest, HUNGARY, 2008

Michela Sega, Elena Amico di Meane, Luigi Bergamaschi, Chiara Boveri, Francesca Durbiano, Laura Giordani
PRODUCTION AND CERTIFICATION OF REFERENCE MATERIALS: EXAMPLES OF I.N.Ri.M. ACTIVITIES
Some I.N.Ri.M activities dealing with the preparation of reference standards and the certification of reference materials in the chemical field are presented. Their main characteristics, as well as the description of the used procedures and some indications on the uncertainty evaluation of all the significant sources are given.
1st IMEKO TC24 Conference (MEFNM 2008 - together with TC19 and TC23), Budapest, HUNGARY, 2008

Buzoianu Mirella
RECENT DEVELOPMENTS IN THE PRODUCTION AND USE OF REFERENCE MATERIALS AND MEASUREMENT STANDARDS IN ROMANIA
Reliable, traceable and comparable measurements provide the rational basis for evaluation of the quality of a result and the starting point for laboratory accreditation. Nowadays good measurements are essential not only for manufacturing, science and trade, they also underpin a wide range of aspects of the quality of live, from healthcare to sport. Starting from the role of the National Institute of Metrology (INM) in assuring the traceability of all measurements, regardless their end-use and level of accuracy, the paper depicts some aspects related to the present state-of-art in the field of metrology in chemistry in Romania. The paper reviews locally available reference materials (RMs) and certified reference materials (CRMs) in quality of life related measurements, the experience of the INM in developing new measurement standards and aspects of certification of RMs issued in Romania. Practical examples on the use of CRMs for calibration, traceability and measurement uncertainty evaluation are discussed.
1st IMEKO TC24 Conference (MEFNM 2008 - together with TC19 and TC23), Budapest, HUNGARY, 2008

Franco Pavese
A METROLOGIST ANALYSIS OF INTERNATIONAL WRITTEN STANDARDS AND GUIDES RELEVANT TO MEASUREMENT IN CHEMISTRY
This paper, starting from reviewing basic concepts, such as repeatability, reproducibility, accuracy, systematic error, true value, bias, Type A and B uncertainty components, as defined in international documents, shows that, currently, full consensus and a common understanding seems not be achieved yet. This fact reflects on the process of combining data, namely in chemistry.
1st IMEKO TC24 Conference (MEFNM 2008 - together with TC19 and TC23), Budapest, HUNGARY, 2008

José E. Manzoli, Celso Lemos, Luz C.G.A. Panzarini, Juliana S. Félix, Magali Monteiro
POSSIBLE INDIRECT MEASUREMENT OF DIFFUSION COEFFICIENT FROM MIGRATION KINETIC ESSAY OF FOOD PACKAGING
Diffusion coefficient is an important quantity that affects any migration process on food or nutritional systems. Special care has to be done to migration of undesirable substances from packaging into foods, if the diffusion is the only process involved in mass transfer. The Fick´s equation resolution permits to describe the kinetic of migration from polymer packaging into food or simulant, once it was given the correct contour and initial conditions. Another important quantity is the partition coefficient, which quantifies the relation between the final or equilibrium concentrations in polymer and that in the food or simulant. Here it is proposed a simple procedure, based on numerical resolution of the Fick´s equation, where the diffusion coefficient could indirectly be measured, if the kinetic of migration had been measured and the partition coefficient is known.
1st IMEKO TC24 Conference (MEFNM 2008 - together with TC19 and TC23), Budapest, HUNGARY, 2008

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