The purpose of the study was to develop a new CRM for the composition of the mass fraction of phthalates in a polymer matrix based on polyvinyl chloride for validation and/or verification of measurement methods such as GOST R ISO 8124-6-2021, GOST R ISO 14389–2016, GOST R ISO 16181–2015 etc.

   In the study, a method for preparing the starting material of the CRM was tested and successfully implemented, and a critical analysis of methods for measuring the content of di(n-butyl)phthalate and di(2-ethylhexyl)phthalate was carried out. The gas chromatography/isotope dilution mass spectrometry method was chosen as the main method for a quantitative determination of the certified value of the measured value of the mass fraction of di(n-butyl)phthalate and di(2-ethylhexyl) phthalate. In accordance with RMG 93–2015, GOST 8.315-2019, and GOST ISO Guide 35–2015, the standard uncertainty of the certified CRM value from the characterization method, from heterogeneity and instability of the material was assessed. The expanded uncertainty of the certified value was calculated. As a result of the work, a new CRM for the composition of the mass fraction of phthalates in a polymer matrix based on polyvinyl chloride was approved. Certified CRM values are metrologically traceable to GET 208 in accordance with metrological hierarchy according to the verification schedule through GSO 11366–2019. A CRM composition for the mass fraction of phthalates in polyvinyl chloride has the following standardized metrological characteristics: mass fraction of di(n-butyl)phthalate – 0.046 mg/g and di(2-ethylhexyl)phthalate – 45.8 mg/g; the relative expanded uncertainty at k = 2, P = 0.95 is 10 %. The CRM is stored in sealed bottles in a dry place, protected from light, at a temperature from 2 °C to 8 °C. The shelf life of the CRM is 3 years. The developed CRM can be used in solving any measurement problems and performing various types of metrological work, including metrological purposes in the field of polymer and rubber industries, food industry, environmental protection, and scientific research.

   The article summarizes the history of the creation of the State Primary Standard in the field of organic analysis GET 208 and a description of the standard. The authors outlined the limits of competence and scope of application of GET 208. The issues of developing calibration and measurement capabilities (CMCs) in the field of organic analysis are considered using the example of relevant key comparisons. The CMCs of GET 208 are presented, which are documented in the BIPM database and confirm the equivalence of the Russian state standard and the national standards of other signatories to the CIPM MRA. In addition, information on the possibilities of reproducing, storing, and transmitting measurement units from GET 208 has been systematized in order to ensure the uniformity of measurements and metrological traceability of measurement results in the Russian Federation.

   Issues related to the developmet and improvement of the metrological support system of the Russian Federation in the field of absolute pressure are considered; the main stages and results of theoretical and practical research work in the field of absolute pressure measurements carried out at the D. I. Mendeleyev Institute for Metrology are outlined. Historical information on the creation of primary standards and verification schedules in the field of pressure measurement is presented. A brief analysis of the state and development trends of world metrology in the field of absolute pressure measurement is carried out based on literature data and the results of key comparisons. The reasons for improving the State Primary Standard of the pressure unit in the field of absolute pressure are outlined, and ways to modernize the standard are proposed.The operating principles and design features of reference complexes from the State Primary Standard for the pressure unit in the field of absolute pressure GET 101–2011 are described. The main metrological characteristics of the standard are listed; the results of key comparisons, benchmark studies and international cooperation are published. The existing problems of the reference base of the Russian Federation in the field of absolute pressure and ways to improve the primary standard are outlined and analyzed. The metrological characteristics of the State Primary Standard for the pressure unit in the field of absolute pressure after completion of the modernization are assessed.

   The article deals with the issues of metrological support on the example of the highest level of the State Verification Scheme for measuring instruments of direct current voltage and electromotive force. The origin and development of reference measurements of DC voltage and electromotive force in the Russian Empire, the USSR, and modern Russia is briefly reviewed. The results of work on improving the State Primary Standard GET 13 completed in 2022 are presented.

   Scientific and technological progress in the field of geodetic and industrial measurements in terms of the use of laser rangefinders operating in ranges up to 5000 meters has led to a reduction in the error of such measuring instruments over the past ten years by two or more times. Such rapid development of high-precision rangefinder technologies has led to a significant revision of the requirements for their metrological support, as well as to the need to develop a new generation of length standards, the stock of metrological accuracy of which would provide an assessment of the metrological characteristics of all types of existing and promising length measuring instruments with a laser rangefinder. To solve this problem, the Institute’s staff conducted research within the framework of a number of thematic research and development works in terms of developing the appearance of a new generation of length standards operating in the range up to 5000 meters in an open atmosphere. Within the framework of this article, one of the developed models of a high-precision complex of measuring instruments for length and coordinate increments is considered, which is a serial high-precision laser phase light meter, modified by the institute’s staff in terms of the system for receiving and processing measuring signals. At the same time, in order to increase the accuracy of length measurements using the developed range finder layout, it is proposed to investigate ways to reduce the errors of the model components of the boundaries of its error. To ensure the smallest error in determining the hardware correction of the rangefinder layout, it is proposed to use funds from the state primary special standard of the unit of length. As promising ways to reduce the error in determining the phase difference of signals, it is proposed to use digital recording and signal processing devices that implement a method for calculating the phase difference of signals by mathematically processing the recorded data using a specially developed computational algorithm based on Fourier analysis. For the most accurate determination of the values of the pulse repetition frequency of signals and the values of the speed of light on the measured track, it is proposed to improve the means of determining these indicators. The use of the proposed methods to improve the accuracy of measuring the length of laser phase rangefinders allows you to provide the necessary margin of metrological accuracy.

   Establishing the pinpoint accuracy of national primary standards for units of mass and volume flow rates (mass and volume) of liquid (water) is a priority in the national economy of most states. In Russia and abroad, the principle of operation of standards for units of flow rate and amount of liquid is based on the gravimetric weighing method, i. e., on measuring the mass of liquid entering a weighing container over a certain averaging time interval. The decisive condition for the accuracy of the result of the standard is the stabilization of liquid flow rate, as well as the choice of the optimal method for creating a forced flow of liquid in the pressure pipeline and measuring line. The widely accepted method of creating a forced flow of liquid by placing it at a height or supplying it using pumps has one inconvenient consequence – the bulkiness of the standard design. The creation of such a design entails economic, labor, and time costs, which can adversely affect the test conditions and results. The author’s innovative method of active damping of pressure and fluid flow fluctuations, which eliminates the need to place the pressure tank at a great height above ground level, allows minimizing inconveniences. This method is implemented in the pressure pipeline and measuring line of the reference installation 3 of the State Primary Special Standard of Units of Mass and Volume of Liquid in a Flow and of Mass and Volume Flow Rates of a Liquid GET 63–2019.

   The purpose of the article is to substantiate and experimentally confirm the high efficiency of this method.

   The results of experimental research of changes in the absolute pressure in the air cushion and the liquid level in the pressure tank of the stabilization module confirmed the efficiency of the proposed method based on the obtained minimum values of the relative deviations of the instantaneous and average liquid flow rates. The engineering solution presented in the article is of interest to economic entities and commercial organizations interested in reducing the costs of testing the volumetric flow rate (mass and volume) of liquid (water).

   The register of approved types of reference materials is intended for registration of reference materials, type standards of which are approved by the Federal Agency for Technical Regulation and Metrology, and presend in the section of the Federal Information Fund for Ensuring the Uniformity of Measurements “Approved standards” py standard samples". Maintenance of the Federal Information Fund, including provision of documents contained thereinт and information, organized by the Federal Agency for Technical Regulation and Metrology. Maintaining a section of the Fund on standard samples of the composition and properties of substances and materials in accordance with part 9 of article 21 of the Federal Law of June 26, 2008 No. 102-FZ “On ensuring the uniformity of measurements” (hereinafter referred to as Federal Law No. 102-FZ) is carried out by the State Service for Standard Samples of Composition and properties of substances and materials. The fund is created to meet the needs of citizens, society and the state in obtaining objective of reliable and reliable information in accordance with Part 1 of Article 20 of Federal Law No. 102-FZ, used in the whole to protect the life and health of citizens, protect the environment, flora and fauna, ensure national defense and security, including economic security.

   An analysis by the Federal Information Fund revealed the lack of methods for measuring the volume fractions of nitrous oxide, carbon oxide and dioxide, oxygen, nitrogen, and non-condensable gases in medical nitrous oxide using portable devices. Nitrous oxide is widely used in medicine, and therefore this research was committed to the development and certification of a method for measuring volume fractions of nitrous oxide, carbon oxide and dioxide, oxygen, nitrogen, and non-condensable gases using gas chromatography in medical nitrous oxide. Certification of the measurement method in accordance with legal requirements in the field of ensuring the uniformity of measurements was carried out by organizing a quasi-interlaboratory experiment; the following approaches were used to obtain the measurement result: the method for constructing a calibration dependence, the external standard method, and the calculation method. In addition, the study presents an algorithm and results for calculating the uncertainty of measurements of volume fractions of gases, subject to the provisions of EURACHEM CITAC, as well methodologically influencing factors that were assessed using a multifactorial experiment and its processing by regression analysis.

   Continuous glucose monitoring (CGM) systems are often used to monitor blood glucose levels. Most commercially available CGM systems continuously measure glucose concentrations in the interstitial fluid of subcutaneous adipose tissue. However, there is currently no internationally accepted reference method for measuring interstitial fluid glucose, which is a prerequisite for metrological traceability of glucose measurements obtained using CGM. Since manufacturers do not provide information about the traceability chain and measurement uncertainty of their systems, CGM-derived glucose values cannot currently be adequately traced to standards or higher order reference measurement procedures. Additionally, the «mean absolute relative difference» (MARD) often used to describe the analytical performance of CGM systems is dependent on many factors. For example, the MARD can be significantly affected by the «lag time» between the change in blood glucose and interstitial glucose, especially at high rates of change in glucose. Finally, modern automated insulin delivery (ADI) systems with integrated CGM can automatically suspend or increase insulin infusion in response to current and/or predicted hypoglycemic and hyperglycemic phenomenon in children and adults with type 1 diabetes mellitus (T1DM).

   The purpose of the review is justification of the necessity to establish metrological traceability of glucose measurements with CGM systems, as well as a discussion of the analytical and clinical characteristics of CGM systems proposed by various professional communities.

   Based on the results of the review, it was concluded that it is necessary to 1) develop metrological support for glucose measurements performed using CGM systems, 2) solve the problems of ensuring the accessibility and usability of CGM systems by patients in real conditions.

   Modern industrialization increases the requirements for the accuracy of identifying allergens, especially those that have a negative impact – soy trypsin inhibitor (STI). Correct determination of the presence of STI in food products containing soybeans is key for product safety control and labeling. The authors set a goal to develop and certify a method for measuring the mass fraction of STI using an enzyme-linked immunosorbent assay – a technique that may increase the specificity of the method and avoid false-negative results.

   The object of research was a method for analyzing food allergens – an enzyme-linked immunosorbent assay carried out with a set of reagents produced by XEMA LLC. In the process of developing the measurement method, the main methodological factors influencing the accuracy of the measurement results were optimized: sample weight, time of its extraction, time and speed of sample centrifugation, ratio of supernatant liquid to ELISA buffer, incubation temperature, interaction time of the allergen-antibody complex with the coloring agent, the wavelength for measuring absorbance, and the maximum time for measuring absorbance after introduction of the stop reagent.

   The developed method was tested during an interlaboratory experiment with the participation of 5 laboratories. Metrological characteristics were established in accordance with RMG 61–2010. The proposed method was certified in accordance with the requirements of GOST R8.563-2009, No. 102–FZ. The method has a wide range of quantitative determination of the mass fraction of STI from 0.5 to 25.0 μg/kg (ppb) with a detection limit of 0.1 μg/kg (ppb) and a relative error of 40 %. Based on the results of the research, the Federal Information Fund for Ensuring the Uniformity of Measurements (FIF) registered a certified method for identifying and quantifying the content of non-infectious food allergens of plant protein origin in samples of all types of food products and objects related to the requirements for food products, swabs taken from working surfaces during production control using reagent kits for an enzyme-linked immunosorbent assay produced by XEMA LLC No. FR.1.31.2022.43884. The method is intended for use in testing laboratories involved in monitoring the quality and safety of manufactured products; it can be used to confirm product compliance with the mandatory requirements established in the Technical Regulations of the Customs Union TR CU022/2012.

   Current regulatory documents in Russia establish the need for testing laboratories to determine such parameters as saturated vapor pressure using the Reid method, air saturated vapor pressure, total vapor pressure of crude oil. In analytical practice, appropriate reference materials are used for measurement quality control, method validation, metrological traceability establishment, and other purposes. In addition, the calculation of various vapor pressure equivalents using correlation equations (DVPE – dry vapor pressure equivalent, RVPE – Reid vapor pressure equivalent, etc.) is regulated by appropriate methods for determining vapor pressure. Vapor pressure is a method-dependent parameter; so many producers of reference materials use interlaboratory experiment as a way to establish a certified value. Thus, when conducting an interlaboratory experiment in the process of certification of reference materials, it was revealed that laboratories can incorrectly interpret the obtained experimental data – consider values of the air saturated vapor pressure, total vapor pressure and even calculated vapor pressure equivalents as the Reid vapor pressure. To solve this problem, the authors of this work set the goal of assessing the equivalence of methods for determining the vapor pressure of oil and oil products used in testing laboratories in order to identify the key characteristics of the stated methods and assess their equivalence. The article discusses methods the vapor pressure determination using an automatic vacuum chamber and a Reid bomb. Various matrices of reference materials (hydrocarbons, gasoline, commercial oil, gas condensate) were investigated, and the calculated vapor pressure equivalents were obtained and compared. It was shown that the air saturated vapor pressure, dry vapor pressure equivalent, Reid vapor pressure equivalent, and total vapor pressure cannot be equated to the saturated vapor pressure values determined by the Reid method. A comparative assessment of methods for determining the vapor pressure of oil and oil products used in testing laboratories can be of assistance to developers of regulatory documents for oil, gas condensate, and motor gasoline, revealing the need to separate the requirements for vapor pressure parameters of the considered objects of analysis and providing empirical material.