The purpose of this work was to develop an accurate osmium (Os) solution standard that is traceable to the International System of Units, the SI. A gravimetric reduction (GR) method was developed to accurately assay the Os in ammonium hexachloroosmate salt, (NH)OsCl, the chosen starting material for the Os solution standard. This GR method was also applied to -200 mesh high-purity Os metal powder, which served as an independent source of Os for comparison. An alkali fusion method was developed to create water-soluble salts from the Os metal GR products of both the (NH)OsCl and -200 mesh high-purity Os metal powder. Quantitatively prepared Os solutions from each of these water-soluble salts were compared by inductively coupled plasma spectrometry, ICP-OES. The purities of the Os starting materials were determined by quantitatively performed trace metallic impurities analysis, by ICP-OES and ICP-MS; the O, N, and H impurities were determined by inert gas fusion analysis. The percent purities of the starting materials were applied as corrections to the Os assay results obtained by GR. The agreement between these Os solutions, corrected for random and systematic errors by error budget analysis, confirmed the accuracy of the Os assay in the (NH)OsCl. The SI traceability of the Os assay in the (NH)OsCl salt was established through the GR procedure and the purity analysis of this material. An SI traceable Os solution standard was gravimetrically prepared from this batch of (NH)OsCl, based on the accurate Os assay and the percent purity of the starting material.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/acs.analchem.1c03033 | DOI Listing |
Phys Chem Chem Phys
January 2025
Institute of Chemistry, University of Tartu (UT), Ravila Street 14a, 50411 Tartu, Estonia.
Experimental potentiometric unified pH (pH) scale is presented in 1,2-dichloroethane (1,2-DCE). The scale was compiled using differential potentiometric measurements, carried out by pair-wise comparisons between solutions. Aqueous standard buffer solutions were used as anchor points, so that the obtained pH values are linked to (, are traceable to) the conventional aqueous pH scale and are expressed as values.
View Article and Find Full Text PDFLancet Reg Health Eur
April 2025
The Research Unit for General Practice and Section of General Practice, Department of Public Health, University of Copenhagen, Copenhagen, Denmark.
Background: Addressing the global antibacterial resistance crisis and aligning with the Kyrgyz Ministry of Health's research priorities, this study assesses the efficacy and safety of C-reactive protein (CRP) testing to guide antibiotic prescriptions in children with acute respiratory tract infections (ARTI) in Kyrgyzstan.
Methods: In this open label individually randomised controlled trial, children aged 6 months to 12 years with ARTI in primary care settings were assigned to receive either standard care or standard care plus CRP testing. The study measured two primary outcomes: total antibiotic usage over a 14-day follow-up and caregiver-reported time to recovery.
BMC Public Health
January 2025
Centre for Prevention, Lifestyle and Health, National Institute for Public Health and The Environment, Bilthoven, The Netherlands.
Background: A new paradigm of hybrid working exists, with most office workers sharing their work between the office and home office environment. Working from home increases time spent or prolonged sitting, which is associated with an increased risk of chronic disease. Interventions to reduce sitting time, specifically designed for both the office and home-office environments, are required to address this growing public health issue.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Mathematics, College of Science Al-Zulfi, Majmaah University, Al-Majmaah 11952, Saudi Arabia.
This study aims at investigating the dynamics of sexually transmitted infectious disease (STID), which is serious health concern. In so doing, the integer order STID model is progressed in to the time-delayed non-integer order STID model by introducing the Caputo fractional derivatives in place of integer order derivatives and including the delay factors in the susceptible and infectious compartments. Moreover, unique existence of the solution for the underlying model is ensured by establishing some benchmark results.
View Article and Find Full Text PDFNPJ Vaccines
January 2025
Department of Biochemistry, University of Oxford, OX1 3QU, Oxford, UK.
The rapid development and worldwide distribution of COVID-19 vaccines is a remarkable achievement of biomedical research and logistical implementation. However, these developments are associated with the risk of a surge of substandard and falsified (SF) vaccines, as illustrated by the 184 incidents with SF and diverted COVID-19 vaccines which have been reported during the pandemic in 48 countries, with a paucity of methods for their detection in supply chains. In this context, matrix-assisted laser desorption ionisation-time of flight (MALDI-ToF) mass spectrometry (MS) is globally available for fast and accurate analysis of bacteria in patient samples, offering a potentially accessible solution to identify SF vaccines.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!