An operation (process) as a result of which several microcomponents are isolated in one step. This may be achieved in one of two ways, by transportation either of the matrix or of the microcomponents into a second phase. The first method is widely used in the analysis of relatively simple substances and materials.
Source:
PAC, 1979, 51, 1195
(Separation and preconcentration of trace substances. I - Preconcentration for inorganic trace analysis)
on page 1198