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7 The Analytical Problem
Example 1
Problem: Appraising a drug whose active principle contains two enantiomers (optical isomers) one of which (D) is pharmacologically inactive (why?) while ensuring the presence of
the highest possible proportion of the active one (L) (what for?).
Information required: The proportion of each enantiomer in the finished product (what?)
and in the intermediate steps of the production process (how?). This requires the knowledge
of the raw materials and intermediate products involved (where?, when?) if the proportion of
the active isomer in the product is to be maximized (what for?).
Example 2
Problem: A river is polluted with organic waste from neighbouring factories (why?) .
Information required:Type of industry or raw materials and products involved (what), production steps (how?), waste purifying systems used (how?). production temporality (when?)
and location of the discharge along the river bank (where?).
Example 3
Problem: A forest enclave has been deteriorated by acid rain (why?). The aim is to reduce
the levels of atmospheric pollutants (502, NO. ) released by the neighbouring industries in
order to preserve the trees (what for?, how?).
Information required: Changes in the contents of sulphur, phosphorus, nitrogen, etc., in the
tree leaves and pollutant levels in the atmosphere (what?, when]).
Only with a sound knowledge of the social-economic problem can the analytical problem be
properly approached and the analytical information supplied useful with a view to solving it.
The degree to which the analytical chemist is to be involved in this step will depend
on the technical expertise of his or her interlocutor, who may be an experienced
analytical chemist or a professional with no technical qualifications. This step is
undoubtedly crucial; solving an analytical problem that has not been correctly
approached makes absolutely no sense. Frequently, the analytical chemist is minimally involved in this step - either by tradition or by imposition. One of the differences between classical and modern Analytical Chemistry is the shift from the
traditionally passive role of the analytical chemist in this step to an active one.
I 7.5.2 Pinpointing the Analytical Information Required
In this second step, the analytical chemist must convert the generic chemical
information identified in the first into the analytical information required to
help solve the social-economic problem. By the end of this step, a series of
specific details must be known (see Fig. 7.8). First, the object should be accurately defined and the sampling plan decided upon. Second, the measurands
(analytes) whose presence or concentration is to be determined should be established. Third, the type(s) of analysis to be performed [viz.
(a) qualitative, quantitative or structural;
(b) static, temporal or spatial; and
7 The Analytical Problem
Example 1
Problem: Appraising a drug whose active principle contains two enantiomers (optical isomers) one of which (D) is pharmacologically inactive (why?) while ensuring the presence of
the highest possible proportion of the active one (L) (what for?).
Information required: The proportion of each enantiomer in the finished product (what?)
and in the intermediate steps of the production process (how?). This requires the knowledge
of the raw materials and intermediate products involved (where?, when?) if the proportion of
the active isomer in the product is to be maximized (what for?).
Example 2
Problem: A river is polluted with organic waste from neighbouring factories (why?) .
Information required:Type of industry or raw materials and products involved (what), production steps (how?), waste purifying systems used (how?). production temporality (when?)
and location of the discharge along the river bank (where?).
Example 3
Problem: A forest enclave has been deteriorated by acid rain (why?). The aim is to reduce
the levels of atmospheric pollutants (502, NO. ) released by the neighbouring industries in
order to preserve the trees (what for?, how?).
Information required: Changes in the contents of sulphur, phosphorus, nitrogen, etc., in the
tree leaves and pollutant levels in the atmosphere (what?, when]).
Only with a sound knowledge of the social-economic problem can the analytical problem be
properly approached and the analytical information supplied useful with a view to solving it.
The degree to which the analytical chemist is to be involved in this step will depend
on the technical expertise of his or her interlocutor, who may be an experienced
analytical chemist or a professional with no technical qualifications. This step is
undoubtedly crucial; solving an analytical problem that has not been correctly
approached makes absolutely no sense. Frequently, the analytical chemist is minimally involved in this step - either by tradition or by imposition. One of the differences between classical and modern Analytical Chemistry is the shift from the
traditionally passive role of the analytical chemist in this step to an active one.
I 7.5.2 Pinpointing the Analytical Information Required
In this second step, the analytical chemist must convert the generic chemical
information identified in the first into the analytical information required to
help solve the social-economic problem. By the end of this step, a series of
specific details must be known (see Fig. 7.8). First, the object should be accurately defined and the sampling plan decided upon. Second, the measurands
(analytes) whose presence or concentration is to be determined should be established. Third, the type(s) of analysis to be performed [viz.
(a) qualitative, quantitative or structural;
(b) static, temporal or spatial; and