Common HPLC Calculation Formula

HPLC is a technique used to separate and analyze mixtures of compounds in a liquid phase. It consists of Mobile phase and  Stationary phase. Where, mobile phase used to elute the compounds from the column. and stationary phase interacts with the compounds being separated.

A List of HPLC Calculation Formula

Column efficiency (N)

A measure of how well a column separates compounds, calculated as N = 16(tR/w)^2, where w is the peak width at half height and tR is the retention time.

Peak capacity (n)

The maximum number of peaks that can be resolved in a chromatogram, calculated as n = 5.54(N-1), where N is the column efficiency.

Resolution (Rs)

A measure of how well two adjacent peaks are separated, calculated as Rs = 2∆tR/(w1 + w2), where ∆tR is the difference in retention times and w1 and w2 are the peak widths at half height.

Selectivity factor (Î±)

A measure of how well two compounds are separated, calculated as Î± = k2/k1, where k is the retention factor for each compound.

Retention factor (k)

A measure of how strongly a compound interacts with the stationary phase relative to the mobile phase, calculated as k = (tR - t0)/t0, where t0 is the time it takes for an unretained compound to pass through the column.

Capacity factor (k')

A measure of how much a compound is retained on the column, calculated as k' = (tR - t0)/t0, where t0 is the time it takes for an unretained compound to pass through the column and tR is the retention time of the compound.

The time it takes for an unretained compound to pass through the column.