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Vol 14, No 2 (2024)
Аккредитация лабораторий
How does the Accreditation Body Work?
Abstract
The article discusses the process of accreditation of conformity assessment bodies using the example of the activities of the accreditation body AAC Analitica. All stages of the accreditation process are considered in a comprehensive manner, which allows us to get the clearest possible picture of the functioning of the accreditation body, even for those readers who have never encountered it before. The article also provides explanations on fundamental issues related to the functioning of international accreditation organizations and accreditation activities as such.
100-106
Аналитика веществ и материалов
Modern Approaches to Measuring the Mass Concentration of 1,1-Dimethylhydrazine in Water Using Chromatographic Methods
Abstract
This review discusses the advantages and disadvantages of chromatographic approaches proposed in the scientific literature for the determination of J,JPdimethylhydrazine QUDMHS in water with the aim of providing information that can be useful in the development of highly sensitive methods for measuring the mass concentration of UDMH in water bodies at levels corresponding to current hygienic standards. The use of methods of highPperformance liquid chromatography _ tandem mass spectrometry with prePcolumn derivatization of the analyte can be considered promising. There are few official methods for quantitative determination of NDMH in aqueous samples that
meet the necessary metrological requirements.
144-152
Software for Spectral Data Processing by Chemometrics and Machine Learning Methods
Abstract
The article describes a software package that supports the basic methods of chemometrics, and machine learning used for spectral data processing. The package can be used both as part of the software for analytical spectral instruments or independently. The package contains both common methods Qlinear and quadratic discriminant analysis, principal component regression, and partial least squaresS, as well as lesser known but proven effective in processing spectra, including the random forest method and extreme gradient boosting. Data on the testing of the program are provided, incl. an example of using the developed software package to solve problems of classifying
black carbon particles according to the initial combustion objects.
154-160
Determination of Zinc, Copper, Cadmium and Lead in Beef Liver
Abstract
The results of measurements of the mass fraction of zinc, copper, cadmium and lead using inductively coupled plasma mass spectrometry QICPPMSS and inductively coupled plasma optical emission spectroscopy QICPPOESS in bovine liver samples are presented. Optimal spectrometer parameters for measurements and conditions for sample preparation in a microwave digestion system, as well as a method for preparing laboratory plasticware, were selected. The analytical method was validated by measuring detection limit, limit of quantitation, linearity, precision, and relative bias of the data. The results obtained were compared with certified values and the relative error was assessed. Both methods have been shown to be reliable and can be used to determine the elemental content of bovine liver samples.
162-166
Integrated Geochronological and Geochemical Studies of a Probably Impact Zircon Older than 2.8 Ga in Rocks of the Belomorian Eclogite Province
Abstract
Using laser ablation with inductively coupled plasma, UPThP Pb isotope dating of igneous and metamorphic zircons extracted from aegirineP bearing gneisses in the Gridino melange of the Belomorian eclogite province was carried out. Igneous cores with an age of 2.89-2.83 Ga date of the protoliths. Metamorphic grains and rims yielded an age range of 2.80-1.8 Ga with peaks at ~2.80, 2.75, 2.70 and 1.8 Ga, corresponding to the succession of tectonometamorphic events in the region. Along with typical zircons, the grains with unusual heterogeneous cores, which combine granular, vesicular and vermicular textures, were found. According to Raman spectroscopy the transformations from a crystalline to an amorphous state in them are observed. Microgranular zircons are interpreted as evidence of Mesoarchean impact event ~2.87 Ga or older
168-178
Метрология химического анализа
Metrological Traceability of Measurement Results of Metallurgical Materials Chemical Composition. Practical Questions
Abstract
The results obtained in metallurgy, mechanical engineering, geology, etc. when analyzing matrix materials are expressed in relative units _ the mass fraction of the corresponding element or compound (kg/kg, percentage, etc.) In accordance with the measurement algorithm, the results are traced to the SI unit of mass kilogram.
The metrological characteristics of laboratory balances are important when assessing the
uncertainty of the analytical result. It is shown that their calibration is preferable to verification.
Calibration of universalP purpose analytical instruments is carried out individually with each batch of samples. Accuracy control procedures using CRMs, performed on a regular basis in measurement procedures, confirm the metrological traceability of results. The need for annual verification of analytical instruments in this case seems inappropriate and redundant.
184-186