7.7 The Analytical Problem in the Context of Quality
299
a goods train. A mean content of 9.4 ± 0.2% is supplied that is the result of analysing 232
samples collected according to a statistical sampling plan. There is consistency between the
global information required and that provided by the laboratory, which focussed on correct
planning of the sampling operation.
Figure 7.9, b. There is the need to know whether the water supplied to an agricultural area
is fit for consumption by humans (particularly infants) as nitrate ion (from fertilizers) is toxic
above a given concentration level. Misunderstanding between the client and the analytical
chemist has led to the latter providing the typical parameter values for water (pH, conductivity,cOD,etc.) but not the concentration of the target analyte.The information supplied does
not respond to the social problem, even though it could be used to assess the standard
quality of the water.
Figure 7.9, c. With a view to determining whether water from a particular source has been
made toxic by the potential presence of metal species, the total concentration of each metal
will be inadequate as each may be present in different forms (oxidation states, complex
species, chelates, organometallic compounds) of also different toxicity. On ly a discriminate
determination of each species wi ll provide information consistent with the social-economic
problem addressed.
Figure 7.9, d. For environmental legislation purposes, whether soil near an oil industry is
contaminated with hydrocarbons must be determined. Legislation imposes a limit of 0.1 I1g/
kg to decide whether the soil is polluted. A global response encompassing all types of
hydrocarbons (a liphatic, aromatic, nitrogen- and sulphur-containing, etc.) is thus needed. If
the laboratory implements sophisticated (MPs based on hyphenated techniques such as gas
chromatography-mass spectrometry, it will inevitably provide resu lts of a high internal
quality (e.g. a discriminate listing of the hydrocarbons present in the soil accompanied by
their concentrations, in ppm or ppb, and uncertainties). However, such resu lts will be inconsistent with the information required : ultimately, the client will not know whether the soil is
contaminated as per the applicable legislation. Heavy human work and material expenditure
will have led to useless results. Obviously, the sophisticated (MP used will have to be replaced
with a more simple one providing a global figure encompassing all types of hydrocarbons
rather than discriminate information.
7.7 The Analytical Problem in the Context of Quality
As shown in Chap. 8, the definition of quality encompasses the basic (properties, features) and applied approaches (meeting imposed or implicit needs),
and their mutual relationships, for which analytical chemical counterparts
exist, namely: analytical properties and metrological features (traceability,
uncertainty), and the analytical problem-solving process (see Fig. 7.10). The
relationship between the basic and applied sides of Analytical Chemistry is also
self-obvious and materializes in the different steps of the analytical process.
As shown in Fig. 7.2, properly solving the analytical problem in order to
ensure external quality (i. e. satisfying the client) is thus an essential element of
analytical quality. It is interesting to note that, at present, analytical quality is
299
a goods train. A mean content of 9.4 ± 0.2% is supplied that is the result of analysing 232
samples collected according to a statistical sampling plan. There is consistency between the
global information required and that provided by the laboratory, which focussed on correct
planning of the sampling operation.
Figure 7.9, b. There is the need to know whether the water supplied to an agricultural area
is fit for consumption by humans (particularly infants) as nitrate ion (from fertilizers) is toxic
above a given concentration level. Misunderstanding between the client and the analytical
chemist has led to the latter providing the typical parameter values for water (pH, conductivity,cOD,etc.) but not the concentration of the target analyte.The information supplied does
not respond to the social problem, even though it could be used to assess the standard
quality of the water.
Figure 7.9, c. With a view to determining whether water from a particular source has been
made toxic by the potential presence of metal species, the total concentration of each metal
will be inadequate as each may be present in different forms (oxidation states, complex
species, chelates, organometallic compounds) of also different toxicity. On ly a discriminate
determination of each species wi ll provide information consistent with the social-economic
problem addressed.
Figure 7.9, d. For environmental legislation purposes, whether soil near an oil industry is
contaminated with hydrocarbons must be determined. Legislation imposes a limit of 0.1 I1g/
kg to decide whether the soil is polluted. A global response encompassing all types of
hydrocarbons (a liphatic, aromatic, nitrogen- and sulphur-containing, etc.) is thus needed. If
the laboratory implements sophisticated (MPs based on hyphenated techniques such as gas
chromatography-mass spectrometry, it will inevitably provide resu lts of a high internal
quality (e.g. a discriminate listing of the hydrocarbons present in the soil accompanied by
their concentrations, in ppm or ppb, and uncertainties). However, such resu lts will be inconsistent with the information required : ultimately, the client will not know whether the soil is
contaminated as per the applicable legislation. Heavy human work and material expenditure
will have led to useless results. Obviously, the sophisticated (MP used will have to be replaced
with a more simple one providing a global figure encompassing all types of hydrocarbons
rather than discriminate information.
7.7 The Analytical Problem in the Context of Quality
As shown in Chap. 8, the definition of quality encompasses the basic (properties, features) and applied approaches (meeting imposed or implicit needs),
and their mutual relationships, for which analytical chemical counterparts
exist, namely: analytical properties and metrological features (traceability,
uncertainty), and the analytical problem-solving process (see Fig. 7.10). The
relationship between the basic and applied sides of Analytical Chemistry is also
self-obvious and materializes in the different steps of the analytical process.
As shown in Fig. 7.2, properly solving the analytical problem in order to
ensure external quality (i. e. satisfying the client) is thus an essential element of
analytical quality. It is interesting to note that, at present, analytical quality is