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| 2. |
- Wang, J., et al.
(författare)
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Final report of the CCQM-K145 : Toxic and essential elements in bovine liver
- 2020
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Ingår i: Metrologia. - : IOP Publishing Ltd. - 0026-1394 .- 1681-7575. ; 57:1 A
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Tidskriftsartikel (refereegranskat)abstract
- Liver plays a major role in metabolism and acts as a source of energy for the body by storing glycogen. With the growing interest and investigation in the biological effects in recent years, it is important and necessary to develop accurate and comparable analytical methods for elements in bio-samples. It has, however, been 10 years since the tissue sample (bovine liver) of CCQM-K49 key comparison. The purpose of CCQM-K145 is to ensure the comparable and traceable measurement results for essential and toxic elements such as P, S, Zn, Mn, Ni, Mo, Sr, Cr, Co, Pb, As and Hg in bovine liver among NMIs and other designated measurement bodies worldwide. The comparison was agreed by IAWG as 6th IAWG Benchmarking Exercise with Zn and Ni as exemplary elements at the meeting in Korea in the early October 2016. The results of CCQM-K145 are expected to cover the measurement capability and support CMCs claiming for inorganic elements in the similar biological tissue materials and food samples. 30 NMIs and DIs registered in CCQM-K145. With respect to the methodology, a variety of techniques such as IDMS, ICP-OES, ICP-MS(non-ID), AAS and NAA were adopted by the participants. For Zn, Ni, Sr, Pb and Hg measurements, most participants chose ID-ICP-MS method, which showed the better performance in terms of consistency and reliability of the measurement results. In aspect of the traceability for the measurement results in CCQM-K145, most participants used their own (in house) CRMs or other NMI's CRMs to guarantee trace to SI unit. Most participants used similar matrix CRMs for quality control or method validation. Base on different statistic way to calculate the reference mass fraction values and associated uncertainties for each measurand, removal of the suspected extreme values, and discussion at the IAWG meetings, the median values are proposed as the KCRV for Zn, Ni, Mn, Mo, Cr, Pb and Hg; the arithmetic mean values are proposed as the KCRV for P, S, Sr, Co and As. In general, the performances of the majority of CCQM-K145 participants are very good, illustrating their measurement capabilities for Zn, Ni, P, S, Mn, Mo, Sr, Cr, As, Co, Pb and Hg in a complex biological tissue matrix. Bovine liver contains many kinds of nutrients and microelements, it can be regarded as a typical representative material of biological tissue and food. In CCQM-K145, the analytes involved alkali metals and transition elements, metalloids/semi-metals and non metals with a range of mass fraction from mg/g to μg/kg. CCQM-K145 also tested the ability of NMIs/DIs to determine elements that were easy to be lost and polluted, and interfered significantly. The chemical pretreatment methods of samples used in the comparison is suitable for general food and biological matrix samples. A variety of measurement methods used in the comparison represent the main instrumental technology for elemental analysis. Therefore, for supporting CMC claim, CCQM-K145 is readily applicable to measurement of more elements in a wide range of biological materials (including liquids and solids) and meat products. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
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- Babi, Mouhanad, et al.
(författare)
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Efficient Labeling of Nanocellulose for High-Resolution Fluorescence Microscopy Applications
- 2022
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Ingår i: Biomacromolecules. - : American Chemical Society. - 1525-7797 .- 1526-4602. ; 23:5, s. 1981-1994
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Tidskriftsartikel (refereegranskat)abstract
- The visualization of naturally derived cellulose nanofibrils (CNFs) and nanocrystals (CNCs) within nanocomposite materials is key to the development of packaging materials, tissue culture scaffolds, and emulsifying agents, among many other applications. In this work, we develop a versatile and efficient two-step approach based on triazine and azide-alkyne click-chem. to fluorescently label nanocelluloses with a variety of com. available dyes. We show that this method can be used to label bacterial cellulose fibrils, plant-derived CNFs, carboxymethylated CNFs, and CNCs with Cy5 and fluorescein derivatives to high degrees of labeling using minimal amounts of dye while preserving their native morphol. and crystalline structure. The ability to tune the labeling d. with this method allowed us to prepare optimized samples that were used to visualize nanostructural features of cellulose through super-resolution microscopy. The efficiency, cost-effectiveness, and versatility of this method make it ideal for labeling nanocelluloses and imaging them through advanced microscopy techniques for a broad range of applications.
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| 4. |
- Buker, O., et al.
(författare)
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Metrological support for LNG custody transfer and transport
- 2016
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Ingår i: Proceedings of the 17th International Flow Measurement Conference (FLOMEKO 2016).
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Konferensbidrag (refereegranskat)abstract
- In the framework of the ongoing EMRP Joint Research Project (JRP) ENG 60 “Metrology for LNG” (2014-2017), co-funded by the European Union, a number of metrological challenges associated with custody transfer and transport of LNG will be faced. The project consists of four technical work packages (WP), whereby the main objective is to reduce the measurement uncertainty of LNG custody transfer by a factor two. The focus in WP1 is the design and development of a traceable mid-scale calibration standard for LNG mass and volume flow. The goal is to provide traceable mass and volume flow calibrations up to 400 m3/h (180000 kg/h). In WP2, the emphasis is on the development and validation of a LNG sampling and composition measurement reference standard, consisting of sampler, vaporizer, gas standards, and gas chromatography (GC), which will be used to test and calibrate commercially available LNG sampling and composition measurement systems. The priority in WP3 is given to the development and validation of a method for the determination of the methane number, including correlations based on the LNG composition and corrections for traces of nitrogen and higher hydrocarbons. Since physical properties and quantities play an important role in LNG custody transfer, WP4 comprises reference quality density measurements of LNG to validate and improve models for LNG density predictions, the uncertainty evaluation of enthalpy and calorific value calculations and the development of a novel cryogenic sensor for the simultaneous measurement of speed-of-sound and density. The present paper gives an overview of recently achieved objectives within the project and provides an outlook to future activities.
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| 6. |
- Hallström, J., et al.
(författare)
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Worldwide comparison of lightning impulse voltage measuring systems at the 400-kV level
- 2007
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 56:2, s. 388-391
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Tidskriftsartikel (refereegranskat)abstract
- An international comparison of lightning and switching impulse voltage measuring systems was arranged and coordinated by the Helsinki University of Technology (MIKES-TKK), Espoo, Finland, between 1999 and 2002. The number of participants was 26, including the coordinator. This paper summarizes the results obtained by those eight National Metrology Institutes that participated in the comparison. A 400-kV transfer reference measuring system for measuring lightning impulse voltages was prepared by the coordinator. In addition, a 1-kV impulse voltage calibrator system, including calibrators for both standard lightning and switching impulses, was circulated. © 2007 IEEE.
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| 9. |
- Arrhenius, Karine, et al.
(författare)
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Suitability of vessels and adsorbents for the short-term storage of biogas/biomethane for the determination of impurities – Siloxanes, sulfur compounds, halogenated hydrocarbons, BTEX
- 2017
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Ingår i: Biomass and Bioenergy. - : Elsevier BV. - 0961-9534 .- 1873-2909. ; 105, s. 127-135
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Tidskriftsartikel (refereegranskat)abstract
- Biogas is a renewable energy source with many different production pathways and various excellent opportunities to use, for example as vehicle fuel (biomethane). Reliable analytical methodologies for assessing the quality of the gas are critical to ensure that the gas can technically and safely be used. An essential part of any procedure aiming to determine the quality is the sampling and the transfer to the laboratory. One of the greatest challenges is then to ensure that the composition of the sample collected does not change between the time of sampling and the analysis. The choice of the sampling vessel to be used must be made only after fully assessing its short-term stability. In this paper, the results from short-term stability studies in different vessels (cylinders, bags and sorbents) are presented for siloxanes, BTEX, halogenated hydrocarbons and sulfur compounds. Storage of dry gas at high pressure (> 6 MPa) appears to be a good alternative however it is currently challenging to find an optimal treatment of the cylinders for all species to be assessed in biogas/biomethane. At lower pressure, adsorption effects on the inner surface of the cylinders have been observed. The use of bags and sorbent tubes also shows limitation. No existing sorbent tubes are sufficiently universal as to trap all possible impurities and high boiling compounds may adsorbed on the inner surface of the bags walls. Moreover, the presence of water when storing biogas most certainly impacts the storage stability of compounds in most vessels. Using at least two sampling methods for a given compound and comparing results will allow taking into account the eventual effects of water vapour, and adsorption on the inner surface of the vessels.
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| 10. |
- Arrhenius, Karine, et al.
(författare)
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Traceable reference gas mixtures for sulfur-free natural gas odorants
- 2014
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 13:1, s. 6695-6702
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Tidskriftsartikel (refereegranskat)abstract
- The first reference gas mixtures of sulfur-free natural gas odorants that are traceable to the International System of Units (SI) have been produced and their compositions validated. These mixtures, which contain methyl acrylate and ethyl acrylate at amount fractions between 1.1 and 2.1 μmol mol-1, can be used to underpin measurements of sulfur-free odorants, which are increasingly being used to odorize natural gas in transmission networks as they have less harmful properties than traditional sulfur-containing odorants. The reference gas mixtures produced have been shown to be stable in passivated aluminum cylinders for at least 8 months and have been validated (to within 6% or less) by interlaboratory measurements at three National Measurement Institutes. The stability of methyl acrylate and ethyl acrylate in gas sampling bags has been investigated, and the challenges of analyzing 2-ethyl-3- methylpyrazine, which is used as a stabilizer in sulfur-free odorants, are also briefly discussed.
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