Question

Why they have to determine the retention of solution? solvent?

Answer 1

Answer:

The retention factor of a particular material is the ratio of the distance the spot moved above the origin to the distance the solvent front moved above the origin. It can be calculated using the formula: ... Retention factors are useful in comparing the results of one chromatogram to the results of another.

Answer 2

However, in column chromatography, the retention factor or capacity factor (k) is defined as the ratio of time an analyte is retained in the stationary phase to the time it is retained in the mobile phase, which is inversely proportional to the retardation factor. ...