6.1 Basic Definitions and Requirements
67
Reference material (RM): materials sufficiently homogeneous and stable with
reference to specified properties, which has been established to be fit for its
intended use in measurements or in examination of nominal properties.
Clause 5.13, ISO/IEC Guide 99
Several notes are added to the definition of RMs, given in VIM 3, which specified
various requirements. It is highlighted that a given reference material can only be
used for either calibration or quality assurance in a given measurement. The RMs
with assigned quantity values can be used for calibration or for establishing a measurement trueness; those without assigned quality values can be used for establishing
measurement precision.
There are various kinds of RM; for example, pure chemical substances with specified purity, standard solutions of pure chemicals with specified concentration of
given substance, matrix RMs with analyte originally present and with a specified
concentration, matrix RMs with added (spiked) known amount of analyte.
Certified reference materials (CRM): reference material, accompanied by
documentation issued by an authoritative body and providing one or more
specific property* values with associated uncertainty and traceability, using
validated procedures.
Clause 5.14, ISO/IEC Guide 99
*properties can be qualitative (e.g., identity of substance) or quantitative
CRMs and RMs are widely used in chemical laboratories. If used properly, they
can provide important information about the quality of the results. CRMs in the form
of standards of pure substances are most commonly used for the calibration of the
measuring instruments, thus ensuring metrological traceability. CRMs, especially
those mimicking the matrix of test samples, are used for validation—for the evaluation of the recovery of the applied analytical procedure and to determine the accuracy
of the measurement results.
Apart from the definition of CRMs given in VIM 3, several reference material
producers (RMPs) use their own trade name to described their RMs. For example,
ERM
® is the registered trademark for European Reference Materials. The ERM
®
concept is a joint collaboration of major European RMPs who guarantee to: apply
the principles currently available described in ISO 17034 and ISO Guide 35 for
the production of CRMs; demonstrate rigorously homogeneity and stability for all
materials and guarantee the certified value for every single unit over the complete
shelf life of the materials; be transparent in their approach to the production of
CRMs. Another example is the NIST Standard Reference Material
® (SRM)—a
CRM issued by NIST that meets additional NIST-specific certification criteria and
is issued with a certificate or certificate of analysis that reports the results of its
characterizations and provides information regarding the appropriate use(s) of the
67
Reference material (RM): materials sufficiently homogeneous and stable with
reference to specified properties, which has been established to be fit for its
intended use in measurements or in examination of nominal properties.
Clause 5.13, ISO/IEC Guide 99
Several notes are added to the definition of RMs, given in VIM 3, which specified
various requirements. It is highlighted that a given reference material can only be
used for either calibration or quality assurance in a given measurement. The RMs
with assigned quantity values can be used for calibration or for establishing a measurement trueness; those without assigned quality values can be used for establishing
measurement precision.
There are various kinds of RM; for example, pure chemical substances with specified purity, standard solutions of pure chemicals with specified concentration of
given substance, matrix RMs with analyte originally present and with a specified
concentration, matrix RMs with added (spiked) known amount of analyte.
Certified reference materials (CRM): reference material, accompanied by
documentation issued by an authoritative body and providing one or more
specific property* values with associated uncertainty and traceability, using
validated procedures.
Clause 5.14, ISO/IEC Guide 99
*properties can be qualitative (e.g., identity of substance) or quantitative
CRMs and RMs are widely used in chemical laboratories. If used properly, they
can provide important information about the quality of the results. CRMs in the form
of standards of pure substances are most commonly used for the calibration of the
measuring instruments, thus ensuring metrological traceability. CRMs, especially
those mimicking the matrix of test samples, are used for validation—for the evaluation of the recovery of the applied analytical procedure and to determine the accuracy
of the measurement results.
Apart from the definition of CRMs given in VIM 3, several reference material
producers (RMPs) use their own trade name to described their RMs. For example,
ERM
® is the registered trademark for European Reference Materials. The ERM
®
concept is a joint collaboration of major European RMPs who guarantee to: apply
the principles currently available described in ISO 17034 and ISO Guide 35 for
the production of CRMs; demonstrate rigorously homogeneity and stability for all
materials and guarantee the certified value for every single unit over the complete
shelf life of the materials; be transparent in their approach to the production of
CRMs. Another example is the NIST Standard Reference Material
® (SRM)—a
CRM issued by NIST that meets additional NIST-specific certification criteria and
is issued with a certificate or certificate of analysis that reports the results of its
characterizations and provides information regarding the appropriate use(s) of the