preconcentration coefficient

of a desired microcomponent
in trace analysis
This is defined as
K = Q T Q M Q T o Q M o
where Q T and Q T o are the quantities of the microcomponent in the concentrate and in the sample, respectively (mass units or concentration units), and Q M o and Q M and are the quantities of the matrix before and after preconcentration, respectively. If the recovery is 100%, K = Q M o Q M. The terms enrichment coefficient and enrichment factor are not recommended.
Source:
PAC, 1979, 51, 1195 (Separation and preconcentration of trace substances. I - Preconcentration for inorganic trace analysis) on page 1198