9762 papers found
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.
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
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.
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.
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.
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 I 2 / 100 g and 1,438 g I 2 / 100 g), compared to the results from the colorimetric...
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...
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...
The problem of estimation of measurement accuracy characteristics is formulated as a significant methodological problem for metrology. The main stages of the procedure of accuracy characteristics estimating are presented and discussed. The vast variety of the possible estimation of measurement accuracy characteristics is described, taking into account structural aspects. A practical approach for comparison of various accuracy estimates is proposed, which is based on the developed methodology of certification for data processing algorithms.
Soft sensors, based on Elman NNs, have been developed to provide virtual measurements at different locations on the monument surface using as input source only the measurements acquired by an Air Ambient Monitor Station located nearby. Simulation of measurements by trained NN is a useful computational tool to monitor the physical or chemical conditions of the composing materials in a not invasive way, but their accuracy has to be high as analyzed from a metrological and statistical point of view. Two different mathematical and computational tools can be adopted to improve the accuracy of the...