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Pramann A.,Physikalisch - Technische Bundesanstalt | Rienitz O.,Physikalisch - Technische Bundesanstalt | Schiel D.,Physikalisch - Technische Bundesanstalt | Guttler B.,Physikalisch - Technische Bundesanstalt | Valkiers S.,Institute for Reference Materials and Measurements EC JRC IRMM
International Journal of Mass Spectrometry | Year: 2011

: A novel method of isotope amount ratio measurements using state-of-the-art techniques of a double focusing sector field mass spectrometer combined with isotope dilution mass spectrometry (IDMS) has been applied connecting analytical chemistry with metrology in chemistry aiming at the determination of the Avogadro constant (NA). The molar mass M("Si28") and the corresponding isotopic composition of an artificial silicon crystal material highly enriched in the 28Si isotope has been measured for the first time using a combination of a modified IDMS- and a multicollector-ICP-mass spectrometer (MC-ICP-MS) technique. A value M("Si28") = 27.97697027(23) g/mol has been determined. This corresponds to a relative uncertainty urel = 8.2 × 10 -9 (k = 1). From this silicon crystal material two 1 kg spheres were manufactured which are used by the International Avogadro Coordination (IAC) in order to reassess (NA) with an associated relative measurement uncertainty urel(NA) ≤1 × 10-8. The experiment presented here is the advancement and completion of parts 1 and 2 of this series of papers, describing the theoretical and general experimental applicability of the novel method. The current work summarizes the experimental findings aiming at the determination of the molar mass of the "Si28" material with the lowest uncertainty possible so far. The experimental prerequisites and bottlenecks for examining this highly enriched silicon material as well as experimental proofs for the verification of the presented results are described in detail. The experimental results are supplemented by an uncertainty budget according to the Guide to the Expression of Uncertainty in Measurement (GUM). © 2011 Elsevier B.V. All rights reserved. Source


Gallardo J.M.,CSIC - Institute of Marine Research | Ortea I.,CSIC - Institute of Marine Research | Ortea I.,Institute for Reference Materials and Measurements EC JRC IRMM | Carrera M.,CSIC - Institute of Marine Research | Carrera M.,ETH Zurich
TrAC - Trends in Analytical Chemistry | Year: 2013

This review is a critical overview of advances in proteomics applied in food technology, which may be classified into two main topics: (i) authentication of food components as a tool to comply with food-labeling regulations and policies; and, (ii) food-technology research, mainly for the development of fast, reliable methods to detect and to identify spoilage and/or pathogenic microorganisms in food and for the study of changes in food components as a consequence of food processing. © 2013 Elsevier Ltd. Source


de la Huebra M.J.G.,Institute for Reference Materials and Measurements EC JRC IRMM | Vincent U.,Institute for Reference Materials and Measurements EC JRC IRMM | von Holst C.,Institute for Reference Materials and Measurements EC JRC IRMM
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2011

A collaborative study was carried out according to internationally recognised guidelines in order to establish the performance characteristics of an LC/MS method for the determination of the feed additive semduramicin (SEM) in poultry feed at the level (20-25 mgkg -1) authorised within the European Union. Fifteen laboratories participated in the validation study, and all reported results. The content of SEM in the tested materials, provided as blind duplicates, ranged from 11.5mg kg -1, which corresponds to half the mean authorised level, to 45.0 mgkg -1, which corresponds to twice the mean authorised level. All the materials were analysed by the participating laboratories using two different quantification approaches: standard addition and external standard calibration. The relative standard deviation of reproducibility (RSD R) for both quantification approaches varied from 8% to 18%, corresponding to HORRAT values ranging from 0.8 to 1.5, which were therefore in all cases below the critical value of 2.0. Consequently, the proposed analytical method and both quantification approaches can be considered to be fully validated and transferable to the control laboratories and applied for the determination of SEM in poultry compound feed at authorised level within the frame of official control. Further steps in the administrative procedure aiming to adopt the method as part of an ISO/CEN standard are currently ongoing. © 2011 Taylor & Francis. Source

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