8.6 Assessment of Analytical Quality
327
The following are typical examples of quality control activities performed by
analytical laboratories:
(a) Institution and utilization of control charts based on the use of RMs (see
Box 3.15).
(b) Inspection and adjustment of instruments and apparatus in order to ensure
correct performance. Equipment calibration with reference materials containing no analyte is one of the more important actions in this context (see
Sect. 3.5.4.1) as it helps realize traceability.
(c) Examining the purity and stability of reagents and solutions used in CMPs.
(d) Examining the ambient conditions of the whole laboratory (temperature,
moisture, presence of contaminants) or parts of it (e. g. "clean zones" for
trace analysis).
(e) Supervising the sample custody chain to ensure correspondence between
results and samples - and hence traceability of sample aliquots (Sect. 3.6.2).
(f) Using RMs and CRMs to conduct specific checking actions on a CMP. In
some cases, it is advisable to use blind samples (viz. samples of unknown
origin to the operator that are interspersed with those supplied by clients).
(g) Examining the results obtained by applying the same CMP to the same
sample in order to determine the same analyte(s) following any change in
staff or tools (e.g. when the chromatograph usually employed by the
laboratory is replaced with one for routine analyses). In this way, the influence of a variety of factors and their implications on the analytical results
are examined.
8.6 Assessment of Analytical Quality
Quality assessment activities are a substantial part of Quality Assurance and
involve both direct inspection of the results and direct or indirect examination
of quality control and laboratory activities. Such activities can be highly varied
in nature. The most salient types and the actions they give rise to are commented
on below.
8.6.1 Types of Assessment Systems
Figure 8.10 shows three classifications of Quality Assessment systems based on
as many criteria (viz. the answers to the fundamental questions raised). The least
useful of these classifications is that based on the point in time where actions are
carried out (before, during or after the analytical process).
Depending on the nature of the target object and the manner it is examined,
quality assessment activities can be of the qualitative, quantitative or integral
type. Qualitative assessment involves the visual and documentary inspection of
the laboratory and of the analytical processes and quality control systems it uses;
the inspection comprises an in situ examination of the laboratory work, its
327
The following are typical examples of quality control activities performed by
analytical laboratories:
(a) Institution and utilization of control charts based on the use of RMs (see
Box 3.15).
(b) Inspection and adjustment of instruments and apparatus in order to ensure
correct performance. Equipment calibration with reference materials containing no analyte is one of the more important actions in this context (see
Sect. 3.5.4.1) as it helps realize traceability.
(c) Examining the purity and stability of reagents and solutions used in CMPs.
(d) Examining the ambient conditions of the whole laboratory (temperature,
moisture, presence of contaminants) or parts of it (e. g. "clean zones" for
trace analysis).
(e) Supervising the sample custody chain to ensure correspondence between
results and samples - and hence traceability of sample aliquots (Sect. 3.6.2).
(f) Using RMs and CRMs to conduct specific checking actions on a CMP. In
some cases, it is advisable to use blind samples (viz. samples of unknown
origin to the operator that are interspersed with those supplied by clients).
(g) Examining the results obtained by applying the same CMP to the same
sample in order to determine the same analyte(s) following any change in
staff or tools (e.g. when the chromatograph usually employed by the
laboratory is replaced with one for routine analyses). In this way, the influence of a variety of factors and their implications on the analytical results
are examined.
8.6 Assessment of Analytical Quality
Quality assessment activities are a substantial part of Quality Assurance and
involve both direct inspection of the results and direct or indirect examination
of quality control and laboratory activities. Such activities can be highly varied
in nature. The most salient types and the actions they give rise to are commented
on below.
8.6.1 Types of Assessment Systems
Figure 8.10 shows three classifications of Quality Assessment systems based on
as many criteria (viz. the answers to the fundamental questions raised). The least
useful of these classifications is that based on the point in time where actions are
carried out (before, during or after the analytical process).
Depending on the nature of the target object and the manner it is examined,
quality assessment activities can be of the qualitative, quantitative or integral
type. Qualitative assessment involves the visual and documentary inspection of
the laboratory and of the analytical processes and quality control systems it uses;
the inspection comprises an in situ examination of the laboratory work, its