Rationale. The task of import substitution in health care and the development of normative legal acts in the framework of the Eurasian Economic Community raises the questions of harmonization of national requirements with international ones, including the standardization of drugs. Thereby, the assessment of the quality of domestic recombinant human erythropoietin in accordance with European Pharmacopoeia requirements is very actual. The main indicator of drug quality is specific activity of drug (rhepo). In Russian Federation it is determined by the influence of the drug on erythropoiesis stimulation. This effect of erythropoietin is measured by counting the number of reticulocytes using the flow cytometry and light microscopy. The latter method of calculation is not included in European Pharmacopoeia. Adequate assessment of this indicator is required for the development of national requirements for quality control of drugs rhepo harmonized with European Pharmacopoeia. Purpose of the work. The study aimed the comparative evaluation of the accuracy of the specific erythropoietin activity determination method using the flow cytometry and light microscopy data to provide the harmonization of the draft General monograph with European Pharmacopoeia. Research methods. The erythropoietin specific activity was determined in vivo in normocythaemic mice using the flow cytometry in accordance with the European Pharmacopoeia and light microscopy. We have compared the effects of two independent dilution series of erythropoietin European Pharmacopoeia standard sample. Results. The results of specific erythropoietin activity determination obtained by two different methods of measurement differed in the offset from the reference value (certified value). In flow cytometry data, the offset varied between 1-8%, the results of light microscopy showed higher variability ranging from 4 to 31%. The estimation of intermediate precision showed twice lower dispersion of specific erythropoietin activity measurements obtained by flow cytometry in comparison with light immersion microscopy data. Conclusion. Specific erythropoietin drug activity determination with flow cytometry is characterized by high accuracy and meets the European Pharmacopoeia requirements. We have considered the possibility of light microscopy usage for the same task in the absence of a flow cytometer. The usage of light microscopy requires increasing its accuracy in order to harmonize the method with European Pharmacopoeia requirements.

Actuality of the research. Development of standard samples (SS) of food colour content continues to be relevant to enhance safety and quality of food products, additives and other micro-ingredients as well as to deal with import substitution. Work objective. The objective of this work is to develop SS for the basic substance and toxic elements in the most frequently used in food technologies synthetic food colours: Tartrazine E102, Yellow Quinoline E104, Azorubine E122 and Ponseau 4R E124. Research techniques. Mass fraction of colour in the samples was determined by spectrophotometry as per 320502013 GOST Standard; colour samples for toxic elements were evaluated according to 26929-94 GOST Standard; content of lead and cadmium was determined by atomic absorption analysis defined in the GOST 30178-96, arsenic -by calorimetry as per GOST 26930-94, mercury - by flameless atomic sorption spectrometry according to MU № 5178-90, homogeneity and shelf life - in conformity with RMG 93-2009, GOST 8.531-2002 and Р 50.2.031-2003. Results. SS for the content of four food colours were developed based on the research findings. Their following metrological specification is given in the Table 6: mass fraction of the basic substance, %, fractional error limits (P = 0,95), S, %; content of toxic elements, mg/kg with fractional error limits, S, %.

Rationale. The reference material of composition with the established metrological characteristics including a certified value and an expanded uncertainty is necessary to ensure an effective accuracy and precision control of results of element composition determination in food ingredients and products. This paper represents the development of a reference material of food crop composition for selenium, nitrogen, phosphorus and potassium content. Methods. To identify the selenium the hybrid atomic absorption method was used, to identify the nitrogen and phosphorus the photometric method was used, to determine the potassium flame-photometric method was used. When determining the metrological characteristics of the reference material the Russian national instructions and recommendations MI 3174-2009 and P 50.2.058-2007 were applied. Results. Based on the research findings the reference material of Chinese cabbage composition with a certified value and an expanded uncertainty was developed: for selenium 0.044 ± 0.017 mg/kg; for nitrogen 4.09 ± 0.27 %; for phosphorus 0.69 ± 0.14 %; for potassium 2.87 ± 0.22 %.

Development and introduction of new metallurgical technologies, new additional chemical compound indexes controlled in metallurgical materials demand to develop the new, more advanced methods of analytical control. The particular attention should be paid to identify the traces of stannic, stinium and lead because of their influence on metal characteristics.

The paper represents general information of use of reference material (RM) of composition of toxic metal solutions and RM of composition of biological tissues which contain toxic metals (TM) when measuring the TM content in biological materials. The paper describes and analyses the approaches for preparing samples of reference materials which contain Pb, Hg, Cd, Be and TI, developed by the Institute of Toxicology Federal Bio-Medical Agency of Russia and Ural Research Institute for Metrology. When developing, approving and certification of the relevant measurement methods for TM content in biological materials it is necessary to include, as an essential condition, the requirement to use RM of composition of biological tissues which analyte is naturally built in the material matrix as a result of metabolic process. The analogical requirement should be produced when accrediting and licensing medical and biological laboratories and laboratories of chemical and analytical control.

The relevance of the study. For metrological support of control methods for composition ofpotassium fluozirconate, used in the production of metallic zirconium, applied in various technical fields, including nuclear power, electronics, chemical engineering. The purpose: development of synthesis technology, and determination of metrological characteristics of certified reference material for composition ofpotassium fluozirconate (set), intended for metrological support of measuring element mass fraction: hafnium (Hf), silicon (Si), iron (Fe), aluminium (Al), chromium (Cr), tin (Sn), titanium (Ti) in potassium fluozirconate. Research methods: X-ray diffraction, differential scanning colorimetry, thermogravimetric analysis, atomic-emission spectral analysis with arc excitation, mass spectral analysis, X-ray fluorescence analysis. Results. As a result of research a set of certified reference materials for composition of potassium fluozirconate is developed and produced. The CRM type is approved by Federal Agency on Technical Regulating and Metrology and registered in State Register of Approved Reference Material Types under number GSO 10593-2015.

The International Organization for Standardization laid down modern requirements for reference material producers (ISO 17034:2016), testing and calibration laboratories (ISO 15025:2005), stipulating the evaluation of reference material commutability in the course of their development (ISO Guide 35:2006) and use (ISO Guide 33:2006). The article deals with general issues of reference material commutability evaluation, the cases when the commutability evaluation is useful and the description of the approach, which may be used in the processing measurement results when evaluating the commutability of reference materials.