Certified reference material is defined as: a reference material, accompanied by documentation issued by an authoritative body and providing one or more specified property values with associated uncertainties and traceabilities using valid procedures.
Thus a certified reference material must meet more stringent metrological requirements than a reference material in terms of the following:
‘accompanied by documentation’ – this is usually a certificate of analysis which in addition to listing certified values and association uncertainties, is required to include other specific details.
‘issued by and authoritative body’ – organisations that issue certificates of analysis are required to be able to demonstrate their competence in this role and must meet certain international criteria. These organisations are often accredited as national standards organisations (e.g. NIST– the US National Institute for Standards and Technology), national geological surveys or international organisations (e.g. IAG – the International Association of Geoanalysts).
‘providing one of more specific property values with associated uncertainties and traceabilities using valid procedures’ – thus certified values must be accompanied by an uncertainty and evidence of traceability.