Standard gas mixtures – indispensable reference materials in the analysis of gaseous media

In recent years the need for the quality control and assurance of analytical measurement results has been particularly strongly emphasised. Certified reference materials play an invaluable role in this process. The article characterises the basic types of reference materials, focusing in particular on those in the gaseous state. It also reviews the literature on the techniques of preparing standard gas mixtures over the last ten years (1999–2009) and highlights the main developments in this field.