What types of reference materials are there

Reference materials can be categorised according to a variety of criteria, for example, field of application, form of material, matrix type, intended use in the measurement process and specified properties. The categorisation according to the specified properties is useful for a general overview.

Reference materials are available for the following categories of specified properties:

A Chemical composition

Reference materials (RMs), being either pure chemical compounds, mixtures thereof, or representative sample matrices, either natural or with added analytes, characterised for one or more chemical or physicochemical properties, for example, metal RMs (ferrous/non-ferrous and their alloys), environmental RMs (soil, water, biological materials), gases, solutions (e.g. pH buffers).

B Biological and clinical properties

Materials similar to Category A, but characterised for one or more biochemical or clinical functional properties, for example catalytic activity of an enzyme, taxonomic identity of a microorganism.

C Physical properties

Materials characterised for one or more physical properties, for example optical properties (refractive index, spectral absorbance), electrical/magnetic properties (e.g. dielectric strength, magnetic susceptibility), radioactivity, thermodynamic properties (e.g. thermal conductivity, thermal resistance), physicochemical properties (e.g. viscosity, density).

D Engineering properties

Materials characterised for one or more engineering properties, for example sizing, hardness, tensile strength, surface characteristics, impact hardness, elasticity, etc.

E Others

For example, materials to determine the quality properties of wheat flour, such as water absorption, processing and dough characteristics.

For additional information see:

[1] ILAC – G12 (2000) Guidelines for the requirements for the competence of reference materials producers
(http://www.ilac.org/documents/ILAC_G12-2000_guidelines_for_the_requirements_for_the_competence_of_reference_materials_producers.pdf)

[2] ISO-Guide 34 (2000) General requirements for the competence of reference materials producers

[3] ISO-Guide 33 (2000) Uses of certified reference materials