56
2 Analytical Properties
samples, object, analytical problem and underlying economic, social, scientific
and technical needs via an unbroken chain of relationships where each link
represents one level in the previous hierarchy (see Chap. 3).
Box 2.6
The analytical property representativeness is illustrated here with a specific example as an
advance of the many discussed in dealing with the analytical process in Chap. 7.
Gold found in a mining area! In fact. a rock was analysed at the laboratory and found to
contain 12 mg/kg of the precious metaLThis result is consistent with the sample analysed but
any further concl usions are unwarranted. In fact, whether mining for gold in the area would
be profitable is an industrial problem that must be solved by addressing an analytical
problem - subject to the technical profitability constraints imposed by the mining company -;
this latter will entail sampling a wide zone (the object) to an appropriate depth. The
laboratory will receive many samples allegedly representative of the object that will be
analysed in accordance with the analytical problem. The results thus obtained should be
consistent with (a) the samples received, (b) the zone explored, (e) the analytical problem and
(d) the mining company's problem. If the information produced solves the last, then absolute
representativeness will have been achieved.
The analytical property representativeness encompasses qualitative and quantitative connotations. At the upper consistency levels, intangible aspects become
relevant. At the lowest two, Chemometrics (Statistics) provides indispensable
technical support (e.g. statistical rules for sampling). The analytical problem can
be approached via Statistics, with assistance from Society, Industry, Science and
Technology inputs in stating their information needs. Obviously, for Analytical
Chemistry to ensure the maximum possible representativeness in its actions, it
must establish effective two-way links with other areas.
I 2.S Basic Analytical Properties
There are three basic analytical properties: precision, sensitivity and selectivity.
"Proper sampling", one other basic analytical goal, is strictly not an analytical
property.
As can be seen in the scheme of Fig. 2.1, these properties are at the second level
in the significance hierarchy for analytical properties and provide the strongest
support (foundation relationships) for capital analytical properties, the magnitude of which depends on them. No accuracy is possible without adequate
precision, sensitivity and selectivity. Also, no representativeness can be claimed
in the absence of proper sampling.
Basic analytical properties, in addition to accessory properties, characterize
the analytical process. Section 2.7 discusses the complementary and contradictory relationships among the former and with the other types of properties.
There follows a non-exhaustive description of the more relevant aspects of each
property that is consistent with the approach adopted throughout this book.
2 Analytical Properties
samples, object, analytical problem and underlying economic, social, scientific
and technical needs via an unbroken chain of relationships where each link
represents one level in the previous hierarchy (see Chap. 3).
Box 2.6
The analytical property representativeness is illustrated here with a specific example as an
advance of the many discussed in dealing with the analytical process in Chap. 7.
Gold found in a mining area! In fact. a rock was analysed at the laboratory and found to
contain 12 mg/kg of the precious metaLThis result is consistent with the sample analysed but
any further concl usions are unwarranted. In fact, whether mining for gold in the area would
be profitable is an industrial problem that must be solved by addressing an analytical
problem - subject to the technical profitability constraints imposed by the mining company -;
this latter will entail sampling a wide zone (the object) to an appropriate depth. The
laboratory will receive many samples allegedly representative of the object that will be
analysed in accordance with the analytical problem. The results thus obtained should be
consistent with (a) the samples received, (b) the zone explored, (e) the analytical problem and
(d) the mining company's problem. If the information produced solves the last, then absolute
representativeness will have been achieved.
The analytical property representativeness encompasses qualitative and quantitative connotations. At the upper consistency levels, intangible aspects become
relevant. At the lowest two, Chemometrics (Statistics) provides indispensable
technical support (e.g. statistical rules for sampling). The analytical problem can
be approached via Statistics, with assistance from Society, Industry, Science and
Technology inputs in stating their information needs. Obviously, for Analytical
Chemistry to ensure the maximum possible representativeness in its actions, it
must establish effective two-way links with other areas.
I 2.S Basic Analytical Properties
There are three basic analytical properties: precision, sensitivity and selectivity.
"Proper sampling", one other basic analytical goal, is strictly not an analytical
property.
As can be seen in the scheme of Fig. 2.1, these properties are at the second level
in the significance hierarchy for analytical properties and provide the strongest
support (foundation relationships) for capital analytical properties, the magnitude of which depends on them. No accuracy is possible without adequate
precision, sensitivity and selectivity. Also, no representativeness can be claimed
in the absence of proper sampling.
Basic analytical properties, in addition to accessory properties, characterize
the analytical process. Section 2.7 discusses the complementary and contradictory relationships among the former and with the other types of properties.
There follows a non-exhaustive description of the more relevant aspects of each
property that is consistent with the approach adopted throughout this book.