TABLE OF CONTENTS Of the two terms, reference materials and standards, the latter has so many meanings that care needs to be taken in its use. For example, is the analyst talking about the standard of the work (i.e. the analysis), the standard solutions prepared or the standard method used. Reference material has a much less ambiguous meaning in the analytical laboratory.
Reference materials provide analysts with a common reference point, i.e. when analysing a reference material there is some property of the material that can be referred to which is well defined or characterised. Some of the terms associated with reference materials are:
Certified reference material (CRM)
In-house reference material
Matrix reference material
Natural matrix reference material
Reference material
Traceability
The ISO definition of a Reference material (RM) is "a material or substance one or more of whose property values are sufficiently homogeneous and well established to be used for the calibration of an apparatus, the assessment of a measurement method, or for assigning values to materials". [16]
The raison d' tre of reference materials is to provide traceability. Ultimately and ideally all chemical analyses will be traceable to an SI unit, the amount of substance (mole) or mass (kg). In this way, agreement between different analysts, laboratories, and countries is enhanced.
There are a few analytical techniques, e.g. weighing, where it is possible to directly show traceability to an established value. For most cases, e.g. to verify an analytical...
