1.7 Classifications
Traces
(100 ppm)
0.01%
,
33
1%
Micro components
Macro components
t
,
Determinations
Fig. 1.24. Types of analytical chemical determinations according to relative proportion
(percentage) of analyte mass in the sample
Depending on the relative proportions (concentrations) of the analytes in the
sample, the three types of determinations depicted in Fig. 1.24 - frequently, and
improperly, referred to as "analyses" - are possible. Difficulties here also increase
with increase in concentration of the target analytes (see Fig. 1.14.5).
A combination of the classifications in Figs 1.23 and 1.24 results in a variety
of situations of increasing complexity that range from determinations of macro
compounds (present in proportions exceeding 1 %) in macro samples (weighing
over 0.1 g) to determinations of traces (contents below 0.01 %) in ultramicro
samples (weighing less than 0.001 g). The widespread designation "Trace Analysis" is justifiable because it designates a specially adapted analytical process;
however, it is incorrect in the light of the above hierarchies. In any case, one
should never confuse Microanalysis and Trace Analysis.