Optimization of the State verification scheme of instruments for measuring the content of organic components in liquid and solid substances and materials

he basis for three successive revisions of the State Verification Scheme for instruments measuring the content of organic components in liquid and solid substances and materials was the improvement of the State primary standard of units of mass (molar) fraction and mass (molar) concentration of organic components in liquid and solid substances and materials based on liquid and gas chromatography-mass spectrometry with isotope dilution and gravimetry. During each revision, the structure and content of the current document were critically analyzed and attempts were made to optimize the form and content of the State Verification Scheme and adapt one to the specific features of organic analysis. The historically established rules for constructing verification schemes (in accordance with the Standards of the Russian Federation) are well suited for describing the transfer of units of physical values, but have a significant gaps in terms of transferring units of quantity of a substance. The article presents an overview of the main changes which were introduced in the process of functioning and improvement of the State Primary Standard of units of mass (molar) fraction and mass (molar) concentration of organic components in liquid and solid substances and materials based on liquid and gas chromatography-mass spectrometry with isotope dilution and gravimetry from its inception to the present day. The causes and consequences of the changes are reflected. Special attention is paid to the role of State Verification Scheme in ensuring the equivalence of measurements and the formation of a metrological traceability chain to the basic SI unit – mole. The key role of CRMs of composition for metrological support in the field of organic analysis and the importance of harmonization of domestic and international concepts of ensuring the equivalence of measurements are noted. The obtained results are useful for realising the specifics of organic analysis and the features of metrological support for this area of measurements.