Resolution (R)
When two peaks appear in the chromatogram, it is useful to calculate the resolution of the two peaks (R), which gives an idea of how good the separation of the two analytes is. It should normally be higher than 1.5 for good quantification.
R can be measured by comparing the retention time to the peak width as shown on the first equation or by using other parameters (theoretical plate number, selectivity and capacity factor) as shown on the second equation.
Where R is the resolution, tR is the retention time, w is the peak width, N is the theoretical plate number, α is the selectivity and k' is the capacity factor.
From the first equation, B is the species with the longer retention time, and tR and W are the retention time and elution peak width respectively.