The application of reference materials for the composition and properties of natural objects with certified characteristics is the main instrument for ensuring the correctness of the obtained analytical information in radioecological, geological, and other studies. The article presents the experience of the branch of the Institute of Radiation Safety and Ecology of the National Nuclear Center of the Republic of Kazakhstan in the development and certification of reference materials containing technogenic radionuclides and mass fractions of elements. The soil selected from the sites of underground and surface nuclear tests at the «Experimental field» and «Balapan» sites of the former Semipalatinsk Test Site, which has a diverse radionuclide composition (natural and technogenic radionuclides) with a wide range of chemical elements, was chosen as the starting material for production of reference materials. The main purpose of the work is the certification of two reference materials: reference material for the activity concentration of 137Cs, 90Sr, the mass fraction of Zn, Cu, Pb, Cd, Co, Fe, Mn, As in the soil cover of the Semipalatinsk Test Site (KZ.04.01.00007–2020) and reference material for the activity concentration of 152Eu, 60Co, the mass fraction of Zn, Cu, Pb, Cd, Co, Fe, Mn, As in the soil cover of the Semipalatinsk Test Site (KZ.04.01.00008–2020).
All procedures necessary for the creation of reference materials were carried out: separation of the magnetic fraction from the bulk of the material, grinding of the material, control sieve of the material, as well as homogenization with subsequent analytical studies to certify the parameters of reference materials. The methods of gamma spectrometry, beta spectrometry, mass spectrometry, and combined measurement results processing were applied. The results of an interlaboratory comparative test to determine the certified value of the concentrations of the specified radionuclides and elements are given.
Reference materials are soil samples dried to an air-dry state, grinded to a particle size of less than 60 µm, and packaged in hermetically sealed polypropylene containers weighing 200 g. Reference materials have been included in the register of the state system for ensuring the uniformity of measurements and approved as state reference materials of the Republic of Kazakhstan. The scope of reference materials is to provide interlaboratory quality control of tests of analytical laboratories specialized in conducting radioecological complex studies, as well as the development and validation of analytical measurement procedures.

The article considers the notion of oil content as a measurable indicator and provides information on the procedures for measuring the content of petroleum products by IR spectrometry in natural water, drinking water, and treated wastewater. Certified reference materials (CRMs) for petroleum products with certified characteristics of the mass or mass concentration of petroleum products in the matrix were registered in the system of metrological support of measurements. The content of polar petroleum products in the raw material was not taken into account when establishing the certified values of these CRMs; this leads to a significant difference between a certified characteristic of CRMs and the determined indicator of measurement procedures based on the IR spectrometry method. In contrast to CRMs with a certified characteristic in the form of the total content of petroleum products, there was a need to develop CRM for determining the mass concentration of only non-polar and low-polar petroleum products by the IR spectrometry method.
Information about the stages of CRM development is presented: selection and preparation of material, investigation of material stability. The results of CRM certification for certified indicators in the range of 0.05–2.00 mg/dm3 are presented. The correctness of these results was confirmed in accredited laboratories by interlaboratory comparative tests.
The CRM of mass concentration of non-polar petroleum products in a polar organic solvent GSO 11733–2021 was approved. The metrological characteristics of the CRM were established: the range of permissible certified values is 0.1–3.0 mg/cm3, the permissible relative expanded uncertainty of the certified value for k=2 5 %. The traceability to SI units of the certified CRM value is insured.
It has been confirmed that the developed GSO 11733–2021 is intended to control the accuracy of the measurement results of the mass concentration of non-polar petroleum products in drinking water, natural surface water, and treated wastewater using IR spectrometry and can be used for attestation of procedures for measuring the mass concentration of non-polar petroleum products in water by IR spectrometry. The scope of the CRM is environmental protection, quality control of drinking water, natural surface water, and treated wastewater.

The control of the chemical composition of aluminum-based cathodes of the VSDP brand requires a lot of production time, as well as the availability of expensive equipment, which is not suitable for the control of the alloy composition during its smelting. The purpose of this study is to develop a technology for reference material (RM) production for spectral analysis of the VSDP-16 aluminum alloy, which meets the requirements for stability and chemical homogeneity. The RM certified values should cover the alloying range of the alloy for constructing correct calibrations in the calibration of spectrometers.
The RM production technology included: melting of ingots of charge bars from the VSDP-16 alloy in a vacuum induction furnace; atomization of bars to aluminum powder; hot pressing of the resulting powder in a graphite mold on a hot pressing unit at a sintering temperature of 600C and a pressure of 20 MPa (62 kN); mechanical processing of the obtained bars. In the course of the study, the processing methods of RM melting were tested by introducing the main alloying elements and impurities. The RM homogeneity study was carried out, and it was found that the homogeneity characteristic of Sн for alloying elements is less than 1 % of the certified value, which suggests a good distribution of elements in the bulk. The study of the RM chemical composition showed that the content of elements varies and allows the RM application for calibration of spectral equipment. Calibration dependences are constructed based on optical-emission and X-ray fluorescence analyzers. Dependences are linear, which makes it possible to apply RM for calibration of spectral equipment. The developed RM is appropriate for the optical-emission method of analysis, which does not include the dissolution of samples in acids. This allows to reduce labor intensity compared to the inductively coupled plasma atomic emission method by ~3 times and energy consumption by ~3.5 times.
As a result of the study, a set of certified reference materials was developed for the spectral analysis of the VSDP-16 aluminum alloy GSO 11696–2021, the certified values of which are traceable to the unit of mass fraction by direct measurements on the State Primary Standard of units of mass (molar) fraction and mass (molar) concentration of components in liquid and solid substances and materials based on spectral methods GET 196-2015.

The article presents a review and comparison of the requirements of the International Standard ISO 6892-1:2019 and the Interstate Standard GOST 1497-84 establishing a method for measuring the mechanical properties of metals under static tension.
A comparative analysis of the requirements for metrological support of static tension tests for parameters that affect the measuring results of mechanical properties, including test conditions, was carried out.
The main problems of applying GOST 1497-84 are highlighted, which require its harmonization with the International Standard ISO 6892-1:2019 and improvement of the metrological support system for static tension tests in the Russian Federation.
The scheme for ensuring the metrological traceability during static tension testing of the measuring results of mechanical properties to the primary reference measurement procedure, which requires the development of certified reference materials (CRMs) for various test units, was considered.
The authors believe that the proposed systematic approach to ensuring the uniformity of measurements of the characteristics of mechanical properties, using the primary reference methodology as a basis for comparison, will allow laboratories to ensure the reliability of the measuring results of mechanical properties, using not only intermediate precision measures, but also the correctness.