Overcoming challenges regarding reference materials and regulations that influence global standardization of medical laboratory testing results

Background: Standardized results for laboratory tests are particularly important when their interpretation depends on fixed medical practice guidelines or common reference intervals. The medical laboratory community has developed a roadmap for an infrastructure to achieve standardized test results described in the International Organization for Standardization standard 17511:2020 In vitro diagnostic medical devices - Requirements for establishing metrological traceability of values assigned to calibrators, trueness control materials and human samples. Among the challenges to implementing metrological traceability are the availability of fit-for-purpose matrix-based certified reference materials (CRMs) and requirements for regulatory review that differ among countries. A workshop in December 2021 focused on these two challenges and developed recommendations for improved practices. Discussion: The participants agreed that prioritization of measurands for standardization should be based on their impact on medical decisions in a clinical pathway. Ensuring that matrix-based CRMs are globally available for more measurands will enable fit-for-purpose calibration hierarchies for more laboratory tests. Regulation of laboratory tests is important to ensure safety and effectiveness for the populations served. Because regulations are country or region specific, manufacturers must submit recalibration changes intended to standardize results for regulatory review to all areas in which a measuring system is marketed. Recommendations: A standardization initiative requires collaboration and planning among all interested stakeholders. Global collaboration should be further developed for prioritization of measurands for standardization, and for coordinating the production and supply of CRMs worldwide. More uniform regulatory submission requirements are desirable when recalibration is implemented to achieve internationally standardized results.Afdeling Klinische Chemie en Laboratoriumgeneeskunde (AKCL

EXAFS of carbon monoxide oxidation on supported Pt fuel cell electrocatalysts

The potential dependence of the extended X-ray absorption fine structure (EXAFS) obtained at the Pt LIII absorption edge for a carbon supported Pt electrocatalyst exposed to carbon monoxide is presented. The data have been analyzed using the difference file method to separate the dominant contributions of the Pt neighbors from contributions to the EXAFS from the adsorbed species. The presence of adsorbed CO is clearly observed with a Pt-C distance of 1.85 Å at potentials less than 0.5 V vs RHE. Increasing the potential above 0.5 V resulted first in the removal of the adsorbed CO and at more positive potentials, e.g., 1.05 V, in the formation of an oxide layer, as evidenced by the presence of a Pt-O coordination shell at 2.00 Å. These results demonstrate that in situ EXAFS of supported Pt electrocatalysts may be used to probe adsorbate structures

Electrosynthesis, physico-chemical and electrocatalytic properties of a novel electroactive Ru(0) material based on the (Ru(terpy)(CO)) frame (terpy=2,2′:6′,2′′-terpyridine)

International audienceThe preparation of an electroactive material based on a (Ru(terpy)(CO)) frame (terpy/2,2?:6?,2??-terpyridine) has been achievedby the two electron reduction of trans- or cis-[Ru(terpy)(CO)Cl2] complexes. During this electrochemical process, two chlorideligands are released and metal/metal bonds are formed. The highly coloured resulting compound containing Ru/Ru bonds caneither be coated as a film on an electrode surface in acetonitrile electrolyte or generated as a soluble product in DMSO electrolyte.The nature of this material does not depend on the stereochemistry of the starting complex and its characterization, either as a solidand in solution, has been investigated by an interplay between electroanalytical and spectroscopic techniques including 1H-NMR,UV/vis, MS and IR. It appears from the data that one of the possible structure of the material is an oligomeric [Ru(terpy)(CO)]nwith n/3. The trans- and cis-[Ru(terpy)(CO)Cl2] complexes and the related organometallic metal/metal based material displaycatalytic activity in the electroreduction of carbon dioxide in hydro-organic media. Interestingly, [Ru(terpy)(CO)]n modifiedelectrodes also display electrocatalytic activity in purely aqueous solutions

Mesoporous Pt/Ru alloy from the hexagonal lyotropic liquid crystalline phase of a nonionic surfactant

Mesoporous and well-mixed Pt/Ru alloys (1:1 atomic ratio) were prepared by co-reduction of metal salts in the hexagonal Liquid crystalline phase of a nonionic surfactant. Preliminary data indicate that oxidation of carbon monoxide by the mesoporous alloy is more facile than by a commercial platinum catalyst or by mesoporous platinum

Controlled modification of carbon supported platinum electrocatalysts by Mo

A carbon-supported platinum electrocatalyst was modified with molybdenum using surface organometallic chemistry. The catalyst was characterized using transmission electron microscopy, cyclic voltammetry (CV), polarization studies, and in situ fluorescence extended X-ray absorption fine structure (EXAFS) studies. The CV and polarization studies show that CO oxidation starts at low overpotentials. similar to those of a conventionally prepared PtCoMo/C electrocatalyst. EXAFS at the Mo K edge recorded at 0.65 V show that the Mo exists as an oxide species associated with the Pt surface with a Mo-O distance of 1.75 Angstrom. At 0.05 V this oxide is reduced with the formation of a metal-metal bond between the Mo and Ft, with a bond distance of 2.63 Angstrom

Liquid crystal phase templated mesoporous platinum alloy

The reduction of metal salts dissolved in the aqueous domains of the lyotropic liquid crystalline phases of surfactants provides a versatile route to a range of mesoporous metals with aligned pore systems having a high degree of spatial periodicity. Here we report that the co-reduction of binary mixtures of metal compounds dissolved in the hexagonal phase of a non-ionic surfactant leads to bimetallic alloy powders that have a long-ranged porous nanostructure and high specific surface areas. These results indicate that the use of liquid crystalline reaction mixtures could provide a new route to alloys of importance for applications in catalysis

Overcoming challenges regarding reference materials and regulations that influence global standardization of medical laboratory testing results

Background Standardized results for laboratory tests are particularly important when their interpretation depends on fixed medical practice guidelines or common reference intervals. The medical laboratory community has developed a roadmap for an infrastructure to achieve standardized test results described in the International Organization for Standardization standard 17511:2020 In vitro diagnostic medical devices - Requirements for establishing metrological traceability of values assigned to calibrators, trueness control materials and human samples. Among the challenges to implementing metrological traceability are the availability of fit-for-purpose matrix-based certified reference materials (CRMs) and requirements for regulatory review that differ among countries. A workshop in December 2021 focused on these two challenges and developed recommendations for improved practices. Discussion The participants agreed that prioritization of measurands for standardization should be based on their impact on medical decisions in a clinical pathway. Ensuring that matrix-based CRMs are globally available for more measurands will enable fit-for-purpose calibration hierarchies for more laboratory tests. Regulation of laboratory tests is important to ensure safety and effectiveness for the populations served. Because regulations are country or region specific, manufacturers must submit recalibration changes intended to standardize results for regulatory review to all areas in which a measuring system is marketed. Recommendations A standardization initiative requires collaboration and planning among all interested stakeholders. Global collaboration should be further developed for prioritization of measurands for standardization, and for coordinating the production and supply of CRMs worldwide. More uniform regulatory submission requirements are desirable when recalibration is implemented to achieve internationally standardized results

Development and Application of a Multifunctional Nanoindenter: Coupling to Electrical Measurements and Integration In-Situ in a Scanning Electron Microscope

International audienceFundamental understanding and quantitative characterization of electron transport mechanisms between two solids brought into mechanical contact require the development of a dedicated multifunctional device. In this study, we report original measurements and analysis based on a nanoindenter coupled with fine electrical measurements in-situ a Scanning Electron Microscope (SEM). After a description of the experimental setup , we report quantitative results on resistive-nanoindentation on metallic systems with increasing complexity. Starting from a model case (Au single crystal), a procedure is developed and further applied to a complex rheology structure (200 nm Au thin film plastically deformed against an elastic substrate) to demonstrate the quantitative monitoring of contact area. Then a two-phase AgPdCu alloy is used to illustrate the resolution of spatial mapping of both mechanical properties and electrical resistance. Finally, we present our experimental results on natively-oxidized Al single crystal. The resistance evolutions during indentation are discussed in terms on dielectric breakdown and electrochemical processes