Support from regulations on the development of reference materials for the compositions of pure organic substances

Abstract

A new approach is proposed to certi~'ing reference materials (RM) for the compositions of pure organic substances, which incorporates the specific features of organic compounds and which meets basic metrological requirements. A program is presented for the metrological certification of such RM.There is a problem in detecting and quantitatively evaluating the contents of toxic organic substances in environmental specimens and lbods, which has become particularly acute in Russia during the last decade since various pieces of legislation have been adopted on protecting the rights of consumers, protecting the environment, health care, obligatory certification of foods as regards safety, and so on. The metrological aspects of it are particularly related to methods of making measurements, whose certification procedures are substantially based on using reference materials (RM) for the compositions of substances.Reference materials for the compositions of pure substances are universal in application because there is wide scope for using them tbr metrological support to the analysis of any material. At the start of the 1980s, there were virtually no RM for the compositions of pure organic substances in this country because although much importance was attached to the analytical chemistry of trace amounts of o~anic substances, it had a place well behind the analysis of inorganic components.Many o~anizations are now developing such RM, which are used in the analysis of drinking water, food products, drag preparations, biological samples, and environmental objects. Some systematization is required in methods of certifying them, together with the development of a unified approach corresponding to the basic concepts in the Russian Federation Law on Providing Unified Measurements, together with various standards [ 1, 2] and other current regulatory documents in the state system of measurements. Moreover, there are in essence two prominent approaches to this topic: some of the developers of RM prefer to use absolute analysis methods, while others prefer interlaboratory certification. In [3], there is a detailed analysis of methods of certifying reference materials, where it is shown that neither of these approaches provides objective metrological establishment of the required regulated characteristics. In general, this is because, on the one hand, there are no absolute methods suitable for analyzing the entire range of organic compounds, while on the other there is an open question of unifying measurements, by which is meant not only the expression of the results in legal units but also the establishment of errors not exceeding set limits.With the above in mind and based on the experience in handling materials coming tbr evaluation in the' head body of the State Reference Materials Service, experts at the. Ural Metrology Research Institute have generated the following general scheme for setting up state reference materials.The new version of the standard [1] deals with the metrological certification of an RM as a research whose ...