Reference materials
External validation of analytical methods

Once confidential, reference materials (RMs), especially when certified, are playing an increasingly significant role in modern analytical sciences. In fact, ISO has set up a special Reference Material Committee (REMCO). It has defined two types of RM:

• simple reference materials, the homogeneity and stability of one or more properties of which have been sufficiently established to make them suitable for the validation of a defined measurement procedure; this definition is fully applicable to the surplus of samples which may be available from a proficiency testing scheme realization (§