Accreditation and Quality Assurance最新文献

A certified reference material (CRM) specifically designed for C-reactive protein (CRP) measurement in clinical laboratories was produced in this study. CRP, a protein synthesized by the liver, serves as an indicator of inflammation when present in elevated concentrations in the bloodstream. The primary goal is to ensure accurate measurement and quality control in accredited clinical laboratories. To achieve this, a recombinant CRP solution was selected as the most suitable candidate material for the CRM due to its exceptional purity. The homogeneity and stability of the developed CRM were thoroughly examined using size exclusion chromatography coupled with ultraviolet detection and high-performance liquid chromatography, (SEC-UV-HPLC). Additionally, traceable amino acid analysis coupled with isotope dilution mass spectrometry (ID-LC/MS-AAA) was employed to determine the protein concentration of CRP in the CRM solution. The evaluation of uncertainties originating from factors such as characterization, homogeneity, long-term stability, and short-term stability data was incorporated to assess the uncertainty associated with the certified CRP value. Consequently, the certified value of the CRM, denoted as UME CRM 1008, was determined to be 43.2 ± 2.2 μmol kg⁻¹, with an expanded uncertainty at a coverage factor of k = 2. The CRP-certified reference material resulting from this study is intended to be used as a primary reference material to enable SI traceable measurement of CRP.

In May, 2023, the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) published the international standard ISO/IEC 17043:2023 Conformity assessment—General requirements for the competence of proficiency testing providers. This article describes the 100 % online revision process from the perspective of the Working Group (WG) members, explains the latest changes, and explores the potential impact of these changes on interested parties.

Chicken serves as an economical and essential source of protein for the human body. However, chickens are susceptible to contamination by various foreign substances, including antibiotics and heavy metals, which can lead to toxicity and resistance within the human body. Therefore, the aim of this present study is to measure the amount of antibiotics in the chicken, especially ciprofloxacin and tetracycline groups using Liquid Chromatography Quadrupole Time of Flight Mass Spectrometry (LC-QTOF-MS/MS). For fulfilment of the aim, the local and imported broiler chicken sample was collected Muscat Governorate, Oman. The chicken breast meat and kidney were placed separately in test tubes for analysis, with subsequent treatment using the necessary chemicals and centrifugation at 4000 rpm and 14000 rpm. The samples were filtered through 0.45-μm nylon filter paper and evaporated. The common antibiotics, namely gentamicin sulphate, sulphanilamide, oxytetracycline, chloramphenicol, and levofloxacin, were detected in the kidney and breast meat within the permissible limit. In local chicken, the highest amount of antibiotics was sulphanilamide followed by oxytetracycline > gentamicin > chloramphenicol > levofloxacin, respectively. However, the imported chicken, the highest amount of antibiotics was sulphanilamide followed by gentamicin > oxytetracycline > chloramphenicol > levofloxacin, respectively. In conclusion, the identified antibiotic residues in chicken breast meat and kidneys do not pose substantial health risks to consumers, as they fall within acceptable limits. The findings do not raise concern for the well-being of the population in Oman.

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Apigenin and gallic acid are advantageous for people's health since they aid in the treatment of liver illness. The study mainly illustrated that a simple, rapid, accurate, economic, and precise UV–visible spectrophotometry method has been developed and validated. Methods are validated according to the ICH guidelines and can be adopted for the routine analysis of gallic acid and apigenin in hepatoprotective polyherbal formulation. Choices of a common solvent were essential so various solvent ranges including methanol, ethanol, and acetonitrile were analyzed. Hence, methanol was selected as a solvent for the proposed method. Gallic acid and apigenin showed maximum absorbance at 217 and 268 nm, respectively. Both drugs obey Beer–Lambert’s law in the concentration range of 0.5 µg mL⁻¹–3 µg mL⁻¹ for gallic acid and apigenin, respectively. The limit of detection and limit of quantification were found to be 0.00379 µg mL⁻¹ and 0.011 µg mL⁻¹ for gallic acid, respectively. For apigenin, the limit of detection and limit of quantification values were found to be 0.00801 µg mL⁻¹ and 0.024 µg mL⁻¹, respectively. The method was validated statistically and by recovery studies for linearity, precision, repeatability, and reproducibility. The obtained results proved that the method can be employed for the routine analysis of gallic acid and apigenin in bulks as well as in the commercial herbal formulations.

Biomethane may contain trace components that can have adverse effects on gas vehicles performances and on the pipelines when injected in the gas grid. Biomethane quality assurance against specifications is therefore crucial for the integrity of the end-users’ appliances. Analytical methods used to assess biomethane conformity assessment must be validated properly and possibly, new methods specifically for biomethane should be developed. This paper provides an overview of the biomethane quality assurance infrastructure and the challenges faced with focus on sampling, analysis methods, reference gas mixtures, and performance evaluation. Currently, requirements for analytical method validation and fit-for-purpose assessments do not exist for biomethane. The industry is in urgent need of a protocol to evaluate the fit-for-purpose of methods in a harmonized manner. Reference gas mixtures to check the accuracy of the instrument and to determine the traceability of the measurement are also urgently required.

In this study, new analytical procedures: microwave plasma-atomic emission spectrometry and wavelength dispersive—X-ray fluorescence for the determination of major elements in ash generated by combustion of solid biofuels such as wood chips and straw were developed and validated. The study also describes the establishment of results’ traceability and comparison of developed methods. The aim of this study was to test reliability of measurement results for total major element content in ash by means of non-destructive X-ray fluorescence method that can be used directly on site. The study was entirely performed within the implementation of the EMPIR 19ENG09 BIOFMET New metrological methods for biofuel materials analysis project.

Based on ISO 17034 and ISO Guide 35, a new series of matrix reference materials for 23 trace elements in 2 mg/mL gold solutions with five concentration levels (0, 1, 5, 10 and 20) ng/mL were developed, respectively. High-purity gold CRM GBW02793 with purity of 99.9995 % used as raw material was dissolved and then doped with multi-element solutions to prepare the candidate RMs. For ICP-MS measurements, matrix-matched and internal standard calibrations were studied and evaluated. The limits of detection (LoDs) ranged from 0.002 to 0.35 ng/mL. The satisfactory spike recoveries from 96 % to 108 % were obtained, demonstrating the measurement trueness. The ICP-MS method was also applied in the homogeneity and stability study. The statistical analysis suggested that the elements were well distributed by measuring 11 units with duplicate analysis for each. Besides, no significant trends were observed in the long-term stability test at room temperature for 12 months or in the short-term stability test at 60 ℃ and − 20 ℃ for 7 days. Through collaborative characterization by eight expert laboratories, the RM at each concentration level was certified for the mass fractions of 23 elements, respectively. All applied measurement methods in the characterization were further validated by using CRM ERM-EB507. The measurement results from all laboratories showed great consistency, and the overall mean values which were consistent with the target values were used as the certified values. Additionally, uncertainties arising from inhomogeneity (u_bb), instability (u_s) and value assignment (u_char) were comprehensively combined. The developed RMs would ensure reliable and traceable analytical results of trace elements in fine gold and gold jewelry.

In many analytical measurements, the analyte concentration in test samples can vary considerably. In such cases, the standard deviation (SD) quantifying measurement imprecision should be expressed as a function of the concentration, c: ({s}_{c}=sqrt{{mathrm{s}}_{0}^{2}+{ s}_{r}^{2}{c}^{2}}), where s₀ represents a non-zero SD at zero concentration and s_r represents a near-constant relative SD at very high concentrations. In the case of SD repeatability, these parameters can be estimated from the differences of duplicated results measured on routine test samples. Datasets with a high number of duplicate results can be obtained within internal quality control. Most procedures recommended for this estimation are based on statistically demanding weighted regression.

This article proposes a statistically less demanding procedure. The s₀ and s_r parameters are estimated from selected subsets of absolute and relative differences of duplicates measured at low to medium concentrations and high to medium concentrations, respectively. The estimates are obtained by iterative calculations from the root mean square of the differences with a correction for the influence of the second parameter. This procedure was verified on Monte Carlo simulated datasets. The variability of the parameter estimates obtained by this proposed procedure may be similar or slightly worse than that of the estimates obtained by the best regression procedure, but better than the variability of the estimates obtained by other tested regression procedures. However, a selection of the duplicates from an inappropriate concentration range may cause a substantial increase in variability of the estimates obtained.

Direct monitoring of volatile organic compounds emitted from industrial sources as well as the monitoring of ambient levels thereof in the atmosphere play an important role in providing data for various legislative requirements. There are many volatile organic compounds emitted to the atmosphere, from biomass burning, power stations, and many other sources. Primary reference gas mixtures of volatile organic compounds containing six components, namely benzene, toluene, ethylbenzene, o-xylene, m-xylene, and p-xylene (BTEX) were prepared by gravimetric methods at nominal amount of substance fractions of 10 µmol/mol. The preparation was performed using the stainless steel (loop) method and direct liquid injection method using gas tight syringe connected to a dedicated syringe heater for comparison purposes. The results of the gravimetric values for both methods were within 1 % of the nominal amount of substance fraction. After the preparation, comparison was achieved by analysis of the BTEX gas mixtures using gas chromatography with flame ionisation detection (GC-FID) and showed comparability to within 2 % of the gravimetric values. The contributions to the uncertainty of measurement were from weighing stainless steel tubes, syringes, and gas cylinders, as well as purity data. The contribution to the uncertainty of measurement from the analysis by GC-FID were repeatability and reproducibility. The combined expanded uncertainty of measurement was between 1.09 % and 3.51 %. The larger deviation from the gravimetric values and associated uncertainty was observed for benzene due to its higher volatility compared to the other components. The BTEX reference gas mixtures prepared in this study are currently being used as a source of traceability in South Africa for air pollution monitoring purposes.