An operation (process) as a result of which the ratio of concentration or amounts
of microcomponents and main macrocomponents increases. This is a particular example
of a separation, but at greatly differing concentrations of components. The ratio
of the masses of the initial and final samples is not of great importance. Frequently,
the main purpose of relative
preconcentration is the replacement of a matrix unsuitable for analysis by a suitable medium. In some
cases, it is difficult to trace a boundary between the absolute and the relative preconcentrations
as, for example, in preconcentration by zone
melting.
Source:
PAC, 1979, 51, 1195
(Separation and preconcentration of trace substances. I - Preconcentration for inorganic
trace analysis)
on page 1197