Free Retention Factor Calculator
Calculate the retention factor (k') in column chromatography from retention time and void time.
min
min
Retention Factor (k')
3.250
Retention Factor (k') vs Retention Time (tR)
Retention Factor (Capacity Factor)
The retention factor k' describes how strongly a compound is retained by the stationary phase relative to the mobile phase.
Formula
k' = (tR - t0) / t0
where tR is the retention time of the analyte and t0 is the void (dead) time. Ideal k' values are 2-10. Below 1, peaks elute near the void and separation is poor. Above 20, peaks are broad and run time is long.
Example Calculation
A peak at tR = 8.5 min with void time t0 = 2.0 min.
- 01k' = (8.5 - 2.0) / 2.0 = 6.5 / 2.0 = 3.25
- 02The compound spends 3.25 times more time in the stationary phase than the mobile phase.
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