scholarly journals Development of in-House Industrial Fluosilicic Acid Certified Reference Material: Certification of H2SiF6 Mass Fraction

Minerals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 92
Author(s):  
Said Kounbach ◽  
Mokhtar Ben Embarek ◽  
Abdeljalil Chemaa ◽  
Rachid Boulif ◽  
Rachid Benhida ◽  
...  
Keyword(s):  
Reference Material ◽  
Certified Reference Material ◽  
Analytical Methods ◽  
Mass Fraction ◽  
International System ◽  
Measurement Data ◽  
Metrological Traceability ◽  
Standard Uncertainty ◽  
System Of Units ◽  
Fluosilicic Acid

Fluosilicic acid is a by-product of the chemical phosphate industry, mainly during the manufacture of phosphoric acid and triple super phosphate (TSP). To ensure the accurate measurement of the H2SiF6 mass fraction in this by-product, method validation is required, which needs a certified reference material (CRM) with its traceability to the International System of Units (SI). This work describes the development of a certified reference material of fluosilicic acid, which is commercially unavailable. Details of all steps, such as sample preparation, homogeneity and stability studies, value assignment, establishment of metrological traceability, and uncertainty estimation of the certified reference material, are fully described. The H2SiF6 mass fraction in the CRM was quantified by two analytical methods, i.e., UV-VIS as a primary method of analysis and flame mode atomic absorption spectroscopy (AAS) as a second method. It is worth noting that the results obtained from each method were in good agreement. The CRM certified value and corresponding expanded uncertainty, obtained from the combined standard uncertainty multiplied by the coverage factor (k = 2), for a confidence interval of 95%, was (91.5 ± 11.7) g·kg−1. The shelf life of the developed CRM is determined to be 1 year, provided that storage conditions are ensured. The developed CRM can be applied to validate analytical methods, improve the accuracy of measurement data as well as to establish the meteorological traceability of analytical results.

scholarly journals Metrological assurance of dioxin measurements. A certified reference material for measuring the dioxin mass fraction in animal fat

2019 ◽  
Vol 14 (3-4) ◽  
pp. 17-32 ◽  
Author(s):  
A. G. Budko ◽  
A. Y. Mikheeva ◽  
A. I. Krylov
Keyword(s):  
Reference Material ◽  
Certified Reference Material ◽  
Mass Fraction ◽  
Metrological Traceability ◽  
Isotopic Dilution ◽  
Animal Fat ◽  
Measurement Results ◽  
Mass Fractions ◽  
Certified Values ◽  
Good Agreement

The paper presents information on the development of a new certified reference material (CRM) for mass fraction of dioxins in animal fat, with established metrological traceability. A procedure for preparing and certifying CRM material is given. The GC–LRMS method with isotopic dilution was used as an analytical method for establishing certified characteristics. The uncertainties due to inhomogeneity and instability of the CRM material were estimated in order to account for their contribution to the uncertainty of certified values. In addition, the results of interlaboratory comparisons (ILC) for an experimental batch of the developed CRM are presented. Measurement results provided by ILC participants are shown to be in good agreement with the certified characteristics of the CRM. The certified values of dioxin mass fractions (PCDF group) in the CRM material are established to vary from 1 to 1000 ng / kg, with the relative expanded uncertainty ranging from 10 to 20 %.

scholarly journals The NIST Johnson Noise Thermometry System for the Determination of the Boltzmann Constant

2017 ◽  
Vol 122 ◽  
Author(s):  
Nathan E. Flowers-Jacobs ◽  
Alessio Pollarolo ◽  
Kevin J. Coakley ◽  
Adam C. Weis ◽  
Anna E. Fox ◽  
...  
Keyword(s):  
International System ◽  
Standard Uncertainty ◽  
Boltzmann Constant ◽  
Correlated Noise ◽  
Johnson Noise ◽  
Noise Thermometry ◽  
Relative Standard ◽  
System Of Units ◽  
Johnson Noise Thermometry

In preparation for the redefinition of the International System of Units (SI), five different electronic measurements of the Boltzmann constant have been performed using different Johnson noise thermometry (JNT) systems over the past seven years. In this paper, we describe in detail the JNT system and uncertainty components associated with the most recent National Institute of Standards and Technology (NIST) determination of the Boltzmann constant: k = 1.380642 9(69) × 10−23 J/K, with a relative standard uncertainty of 5.0 × 10−6 and relative offset of −4.05 × 10−6 from the Committee on Data for Science and Technology (CODATA) 2014 recommended value. We discuss the input circuits and the approach we used to match the frequency response of two noise sources. We present new measurements of the correlated noise of the 4 K on-chip resistors in the quantum-accurate, pseudorandom, voltage-noise source, which we used to estimate the correlated, frequency-dependent, nonthermal noise in our system. Finally, we contrast our system with those used in other measurements and speculate on future improvements.

scholarly journals Characterization of a New Certified Reference Material for Human Cardiac Troponin I

2006 ◽  
Vol 52 (2) ◽  
pp. 212-219 ◽  
Author(s):  
David M Bunk ◽  
Michael J Welch
Keyword(s):  
Mass Spectrometry ◽  
Reference Material ◽  
Certified Reference Material ◽  
Cardiac Troponin ◽  
Troponin I ◽  
Reversed Phase ◽  
Cardiac Troponin I ◽  
Reference Concentration ◽  
System Of Units

Abstract Background: To address the continuing need for the standardization of clinical human cardiac troponin I (cTnI) assays, NIST, with the assistance of the AACC/IFCC Cardiac Troponin I Standardization Committee, has developed a new certified reference material, Standard Reference Material (SRM) 2921: Human Cardiac Troponin Complex. Methods: The concentration of cTnI in SRM 2921 was determined through a combination of reversed-phase liquid chromatography (LC) with ultraviolet detection and amino acid analysis. Characterization of the intact troponin subunits was accomplished through reversed-phase LC coupled with mass spectrometry. Posttranslational modifications to the cTnI in SRM 2921 were investigated by combining proteolytic digestion with matrix-assisted laser desorption/ionization mass spectrometry. Additionally, reference concentration values for cTnT and cTnC were also determined. Results: The concentration of human cTnI in SRM 2921 is 31.2 (1.4) mg/L (where 1.4 mg/L is the uncertainty at a 95% level of confidence), as certified through a method that provides traceability to the International System of Units (SI). Reference concentration values of the cTnT and cTnC subunits were determined to be 36.9 (3.8) mg/L and 24.2 (1.3) mg/L, respectively. Conclusions: This first cTnI reference material should provide SI traceability to clinical cTnI assays once commutability has been validated, and could assist in the international harmonization of cTnI assays as a tool for understanding the underlying causes of interassay variability.

scholarly journals Thermodynamic Properties of Seawater, Ice and Humid Air: TEOS-10, Before and Beyond

2018 ◽  
Author(s):  
Rainer Feistel
Keyword(s):  
Hydrological Cycle ◽  
International System ◽  
Metrological Traceability ◽  
Humid Air ◽  
Ongoing Research ◽  
Seawater Salinity ◽  
System Of Units ◽  
Atmospheric Relative Humidity ◽  
Definition Of ◽  
First Time

Abstract. In the terrestrial climate system, water is a key player in the form of its different ambient phases of ice, liquid and vapour, admixed with sea salt in the ocean and with dry air in the atmosphere. For proper balances of climatic energy and entropy fluxes in models and observation, a highly accurate, consistent and comprehensive thermodynamic standard framework is requisite in geophysics and climate research. The new “Thermodynamic Equation of Seawater – 2010” (TEOS-10) constitutes such a standard for properties of water in its various manifestations in the hydrological cycle. TEOS-10 has been recommended internationally in 2009 by the Intergovernmental Oceanographic Commission (IOC) to replace the previous 1980 seawater standard, EOS-80, and in 2011 by the International Union of Geodesy and Geophysics (IUGG) “as the official description for the properties of seawater, of ice and of humid air”. This paper briefly reviews the development of TEOS-10, its novel axiomatic properties, new oceanographic tools it offers, and important tasks that still await solutions by ongoing research. Among the latter are new definitions and measurement standards for seawater salinity and pH, in order to establish their metrological traceability to the International System of Units (SI), for the first time after a century of widespread use. Of similar climatological relevance is the development and recommendation of a uniform standard definition of atmospheric relative humidity that is unambiguous and rigorously based on physical principles.

Development of Artificial Urine Certified Reference Material for Quantification of Neonicotinoid Insecticides

2020 ◽  
Vol 103 (6) ◽  
pp. 1469-1477
Author(s):  
Takamitsu Otake ◽  
Shoji F Nakayama ◽  
Tomohiko Isobe ◽  
Nobuyasu Hanari
Keyword(s):  
Reference Material ◽  
Health Risks ◽  
Certified Reference Material ◽  
Analytical Methods ◽  
Isotope Dilution Mass Spectrometry ◽  
Raw Material ◽  
Expiry Date ◽  
Neonicotinoid Insecticides ◽  
Artificial Urine ◽  
Exposure Levels

Abstract Background Neonicotinoid insecticides (neonicotinoids) are widely used, however, they can negatively affect human health. Thus, neonicotinoids and their metabolites in human urine are analyzed globally to assess exposure levels and health risks. To properly assess the exposure levels and health risks, accurate analytical results are a necessity. Objective This study aims to develop urine certified reference material (CRM), NMIJ CRM 7408-a, for the quantification of neonicotinoids. Method To develop NMIJ CRM 7408-a, commercially available artificial urine was used as the raw material to which the target neonicotinoids were added. Analyses of neonicotinoids in NMIJ CRM 7408-a were carried out by isotope dilution mass spectrometry (IDMS). Results Sample homogeneity was assessed, with the results showing that acetamiprid, clothianidin, thiacloprid, and thiamethoxam exhibited sufficiently homogeneous distributions in the material. The relative uncertainties due to inhomogeneity were 1.2–7.0%. The results obtained from long-term stability assessment indicated that the target neonicotinoids were stable. The relative uncertainties due to instability were 9.4–17.2% (for an expiry date of 21 months). The characterization for providing concentration values was carried out using one (clothianidin and thiacloprid) or two (acetamiprid and thiamethoxam) analytical methods. The certified values of the target neonicotinoids (acetamiprid, clothianidin, thiacloprid, and thiamethoxam) were 0.19–1.38 µg/kg. Conclusions This is the first frozen artificial urine CRM in which neonicotinoids were quantified by IDMS and will be useful for evaluating the accuracy of analysis and validation of analytical methods for the determination of neonicotinoids in urine. Highlights NMIJ CRM 7408-a, which has been certified for four neonicotinoids, was developed by NMIJ.

Metrological Traceability and Roles of Certified Reference Materials

2016 ◽  
Vol 4 (2) ◽  
pp. 81-83
Author(s):  
Akiharu Hioki ◽  
Keyword(s):  
Reference Materials ◽  
Certified Reference Materials ◽  
International System ◽  
Metrological Traceability ◽  
Chemical Analyses ◽  
International Reference ◽  
Calibration And Validation ◽  
Traceability System ◽  
System Of Units ◽  
Metre Convention

Metrological traceability to an international reference, the International System of Units (SI) if possible, is important for the reliability of measurements. The international traceability system under the Metre Convention is briefly introduced. The simplest way to secure metrological traceability in chemical analyses is to utilise certified reference materials (CRMs) for calibration and validation. Finally, as examples of CRMs, NMIJ ones are described.

scholarly journals Development of an HPLC method with relative molar sensitivity based on 1H-qNMR to determine acteoside and pedaliin in dried sesame leaf powders and processed foods

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243175
Author(s):  
Takashi Ohtsuki ◽  
Kiyoaki Matsuoka ◽  
Yushiro Fuji ◽  
Yuzo Nishizaki ◽  
Naoko Masumoto ◽  
...  
Keyword(s):  
High Performance ◽  
International System ◽  
Analytical Data ◽  
Metrological Traceability ◽  
Hplc Method ◽  
Processed Foods ◽  
Reference Standard ◽  
Food Ingredients ◽  
System Of Units ◽  
The Cost

A high-performance liquid chromatography (HPLC) method with relative molar sensitivity (RMS) based on 1H quantitative NMR spectroscopy (1H-qNMR) has been developed for food ingredients such as acteoside (verbascoside) and pedaliin (pedalitin-6-O-glucoside) without requiring authentic and identical standards as the reliable analytical methods. This method is used methyl 4-hydroxybenzoate (MHB) as an alternative reference standard. Each RMS is also calculated from the ratio of each analyte's molar absorption coefficient to that of MHB after correcting the purities of the analytes and reference standard by 1H-qNMR. Therefore, this method can quantify several analytes with metrological traceability to the International System of Units (SI) using the RMS and one alternative reference standard. In this study, the content of acteoside and pedaliin in several samples, such as dried sesame leaf powders and commercially processed foods, can be determined by the proposed RMS method and demonstrated in good agreement that obtained by a conventional method. Moreover, the proposed method yields analytical data with SI-traceability without the need for an authentic and identical analyte standard. Thus, the proposed RMS method is a useful and practical tool for determining acteoside and pedaliin in terms of the accuracy of quantitative values, the routine analysis, and the cost of reagents.

scholarly journals Thermodynamic properties of seawater, ice and humid air: TEOS-10, before and beyond

Ocean Science ◽  
2018 ◽  
Vol 14 (3) ◽  
pp. 471-502 ◽  
Author(s):  
Rainer Feistel
Keyword(s):  
Thermodynamic Properties ◽  
Hydrological Cycle ◽  
International System ◽  
Metrological Traceability ◽  
Humid Air ◽  
Ongoing Research ◽  
Seawater Salinity ◽  
System Of Units ◽  
Volume Energy ◽  
Definition Of

Abstract. In the terrestrial climate system, water is a key player in the form of its different ambient phases of ice, liquid and vapour, admixed with sea salt in the ocean and with dry air in the atmosphere. For proper balances of climatic energy and entropy fluxes in models and observations, a highly accurate, consistent and comprehensive thermodynamic standard framework is requisite in geophysics and climate research. The new Thermodynamic Equation of Seawater – 2010 (TEOS-10) constitutes such a standard for properties of water in its various manifestations in the hydrological cycle. TEOS-10 was recommended internationally in 2009 by the Intergovernmental Oceanographic Commission (IOC) to replace the previous 1980 seawater standard, EOS-80, and in 2011 by the International Union of Geodesy and Geophysics (IUGG) as the official description for the properties of seawater, of ice and of humid air. This paper briefly reviews the development of TEOS-10, its novel axiomatic properties, the new oceanographic tools it offers and the important tasks that still await solutions by ongoing research. Among the latter are new definitions and measurement standards for seawater salinity and pH in order to establish their metrological traceability to the International System of Units (SI) for the first time after a century of widespread use. Of similar climatological relevance is the development and recommendation of a uniform standard definition of atmospheric relative humidity that is unambiguous and rigorously based on physical principles.The leading thermodynamic properties of a fluid are determined by the relations which exist between volume, pressure, temperature, energy, and entropy … But all the relations existing between these five quantities for any substance …may be deduced from the single relation existing for that substance between volume, energy, and entropy. Josiah Willard Gibbs, 1873b

scholarly journals Establishing SI-Traceability of Nanoparticle Size Values Measured with Line-Start Incremental Centrifugal Liquid Sedimentation

Separations ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 15
Author(s):  
Vikram Kestens ◽  
Victoria A. Coleman ◽  
Jan Herrmann ◽  
Caterina Minelli ◽  
Alex G. Shard ◽  
...  
Keyword(s):  
Particle Size ◽  
Certified Reference Materials ◽  
International System ◽  
Metrological Traceability ◽  
Metrological Reliability ◽  
Limited Information ◽  
System Of Units ◽  
Si Traceability ◽  
Calibration Materials ◽  
Traceability Networks

Line-start incremental centrifugal liquid sedimentation (disc-CLS) is a powerful technique to determine particle size based on the principles of Stokes’ law. As most input quantities of the Stokes equation cannot be easily determined for typical instruments used for this method, an alternative method which depends on calibrating the sedimentation time scale with reference particles has become common practice. Unfortunately, most of these calibration materials (calibrants) come with limited information regarding their metrological reliability (e.g., lack of measurement uncertainties and traceability statements, incomplete measurand definitions). As a consequence, routine particle size results obtained by disc-CLS are mostly only traceable to the calibrant used, and effective comparisons can only be made for those results originating from measurements performed with the same types of calibrants. In this study, we discuss the concept of metrological traceability and demonstrate that particle size results obtained by disc-CLS can be traceable to the ultimate metrological reference, i.e., the unit of length in the International System of Units (SI), the meter. Using the example of two colloidal silica certified reference materials, we describe how laboratories can realize metrological traceability to the SI by simplifying complex traceability networks.

TOWARD THE REDEFINITION OF THE KILOGRAM FROM THE 28Si INTERNATIONAL RESEARCH PROJECT

2013 ◽  
Vol 24 ◽  
pp. 1360001
Author(s):  
KENICHI FUJII
Keyword(s):  
International Research ◽  
International System ◽  
Physical Constant ◽  
Standard Uncertainty ◽  
Research Project ◽  
Avogadro Constant ◽  
Counting Procedure ◽  
System Of Units ◽  
Fundamental Physical ◽  
International Research Project

In the international system of units, the kilogram in the only SI base unit still defined by a material artefact. In order to redefine this unit with a fundamental physical constant, an international research project was launched in 2004 for determining the Avogadro constant, NA, by counting the atoms in an isotopically enriched 28Si crystal. The counting procedure relies on the measurements of the molar and atomic volumes of 1 kg spheres made of the 28Si crystal. In 2011, the project succeeded in measuring the Avogadro constant with a smallest standard uncertainty, 3.0 × 10−8 NA. Because of an unexpected metallic contamination at the surface of the spheres, the measurement uncertainty was larger than the target of the project by a factor of 1.5. In order to further reduce the uncertainty, a new international research project was launched in 2012. Outline of the new project and the improvements of the measurements will be introduced at the forum. Note from Publisher: This article contains the abstract only.

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