148
4 The Measurement Process in Chemistry
and brain) in much the same way as in instruments equipped with a microprocessor and
printer. A gas (or liquid) chromatograph performs a key preliminary operation. Thus, it
separates the analytes from one another and from their interferences; also, the column output is coupled to an on-line detector. Therefore, the chromatograph carries out part of the first
step in addition to the second. An analyser performs, theoretically in a automatic manner, the
three steps of the analytical process; in fact, some sub-step of the preliminary operations is
usually performed by hand (e.g. in clinical chem ical autoanalysers, where samples are collected, stored and transferred to the analyser's autosampler in a manual manner).
Chemical measurement process
- H Ist Step
2st Step
3rdStep l-~
Sensors
Classical qualitative analysis
Gas chromatography
Clinical autoanalyser
Metrological operations are also integral parts of a eMP; in fact, they constitute
an essential landmark inasmuch as realizing traceability in the results entails
checking both the performance of the instruments and apparatus used, and the
signals they produce. Figure 4.5, which is complementary of Fig. 3.9, illustrates
Fig. 4.5. Calibration operations involved in a CMP. For details, see text
4 The Measurement Process in Chemistry
and brain) in much the same way as in instruments equipped with a microprocessor and
printer. A gas (or liquid) chromatograph performs a key preliminary operation. Thus, it
separates the analytes from one another and from their interferences; also, the column output is coupled to an on-line detector. Therefore, the chromatograph carries out part of the first
step in addition to the second. An analyser performs, theoretically in a automatic manner, the
three steps of the analytical process; in fact, some sub-step of the preliminary operations is
usually performed by hand (e.g. in clinical chem ical autoanalysers, where samples are collected, stored and transferred to the analyser's autosampler in a manual manner).
Chemical measurement process
- H Ist Step
2st Step
3rdStep l-~
Sensors
Classical qualitative analysis
Gas chromatography
Clinical autoanalyser
Metrological operations are also integral parts of a eMP; in fact, they constitute
an essential landmark inasmuch as realizing traceability in the results entails
checking both the performance of the instruments and apparatus used, and the
signals they produce. Figure 4.5, which is complementary of Fig. 3.9, illustrates
Fig. 4.5. Calibration operations involved in a CMP. For details, see text