Chapter 6
Reference Materials in Chemical
Measurements
Certified reference materials (CRMs) are essential in the measurements of chemical
properties. They reflect the content of the analyte in the matrix while retaining all
specific interactions in the examined chemical system.
In previous chapters, the general issue of metrological traceability as well as
calibration has been discussed. The purpose of this chapter is to focus on the chemical
standards, namely the reference material (RM) used for achieving traceability in
chemical measurements. The discussion presented in this chapter on chemical RMs
and their use in providing traceability relates primarily to testing and calibration
laboratories that meet the requirements of ISO/IEC 17025:2017.
The main feature of the measurement result is its traceability to the relevant standard (the reference). As previously stressed, in the case of chemical measurements,
providing measurement traceability is much trickier compared with measurements
of physical quantities. As repeatedly stated, this is due to the fact that in the chemical measurements, the result depends not only on the calibration of the measuring
instrument but also on the nature of the test object and the manner in which the
object is prepared for the measurements. In the previous chapter, methods for how
to establish the appropriate references (metrological traceability) were presented for
the subsequent quantities affecting the result. In this context, for some steps of the
measuring procedure it is possible to trace back to SI units, primarily through the
purchase of metrological services in the relevant accredited calibration laboratories
(e.g., balance calibration, purchase of a class A volumetric flask). A direct reference
to the SI is not possible for the result obtained using the measurement procedure in
which the test object (sample) is subjected to various physical and chemical operations. Therefore, an important part of the activity of chemical laboratories is the use
of chemical RMs.
RMs, for which a certified value of the property is known, are a tool to ensure
the traceability of chemical measurements. Assuming that for each chemical task a
suitable certified reference material was available, it would be possible to establish
an infrastructure similar to that existing for the measurement of physical quantities.
Unfortunately, both the measurement procedures used and the variety of objects are
© Springer Nature Switzerland AG 2018
E. Bulska, Metrology in Chemistry, Lecture Notes in Chemistry 101,
https://doi.org/10.1007/978-3-319-99206-8_6
65
Reference Materials in Chemical
Measurements
Certified reference materials (CRMs) are essential in the measurements of chemical
properties. They reflect the content of the analyte in the matrix while retaining all
specific interactions in the examined chemical system.
In previous chapters, the general issue of metrological traceability as well as
calibration has been discussed. The purpose of this chapter is to focus on the chemical
standards, namely the reference material (RM) used for achieving traceability in
chemical measurements. The discussion presented in this chapter on chemical RMs
and their use in providing traceability relates primarily to testing and calibration
laboratories that meet the requirements of ISO/IEC 17025:2017.
The main feature of the measurement result is its traceability to the relevant standard (the reference). As previously stressed, in the case of chemical measurements,
providing measurement traceability is much trickier compared with measurements
of physical quantities. As repeatedly stated, this is due to the fact that in the chemical measurements, the result depends not only on the calibration of the measuring
instrument but also on the nature of the test object and the manner in which the
object is prepared for the measurements. In the previous chapter, methods for how
to establish the appropriate references (metrological traceability) were presented for
the subsequent quantities affecting the result. In this context, for some steps of the
measuring procedure it is possible to trace back to SI units, primarily through the
purchase of metrological services in the relevant accredited calibration laboratories
(e.g., balance calibration, purchase of a class A volumetric flask). A direct reference
to the SI is not possible for the result obtained using the measurement procedure in
which the test object (sample) is subjected to various physical and chemical operations. Therefore, an important part of the activity of chemical laboratories is the use
of chemical RMs.
RMs, for which a certified value of the property is known, are a tool to ensure
the traceability of chemical measurements. Assuming that for each chemical task a
suitable certified reference material was available, it would be possible to establish
an infrastructure similar to that existing for the measurement of physical quantities.
Unfortunately, both the measurement procedures used and the variety of objects are
© Springer Nature Switzerland AG 2018
E. Bulska, Metrology in Chemistry, Lecture Notes in Chemistry 101,
https://doi.org/10.1007/978-3-319-99206-8_6
65