Reference materials: A review

Abstract

Several factors have increased the use of reference materials in laboratories. This can be explained by the fact that the reference materials have several roles, namely: the confirmation of the identity of unknown materials and/or the determination of their properties; the calibration of measuring equipment; the validation of methods; the realization of proficiency tests; etc. To be able to produce and use them, a set of standards and guidelines concerning the subject of reference materials has been established. There are several producers of reference materials in many fields, but finding the right choice is sometimes considered difficult given the multitude of materials to be analyzed that do not correspond perfectly to the reference material, especially in the case of matrices. This makes the market always seek new materials. To develop them, five steps are essential: material preparation, homogeneity study, stability study, characterization, and evaluation of measurement uncertainties. These steps are equally important; the fact of highlighting less than one of them will imply a significant decrease in the quality of the reference material developed. This review seeks to furnish the scientific community with a paper elucidating the functions of these materials in research laboratories, the normative references devised to standardize their production and utilization, the factors influencing their production, and the essential steps for their development.