Resolution Factor, Tailing Factor, Theoretical Plates and Capacity Factor in HPLC

Resolution factor:

Resolution factor shows the accuracy of the quantitative analysis and resolution factor should be greater than 1.5 or specified in the individual monograph. Resolution factor can be calculated by following formula:

R =               2(t₂-t₁)               

          2.70 (W1_h/2+W2_h/2)
W = Peak width

h = Hight

t₁ = Retention time of first peak

t₂ = Retention time of second peak

Related: Calculation of Relative Response Factor (RRF)

Tailing factor:

It should meet the requirements of the individual monograph and can be calculated by following formula:

T = W 0.05

          2F

W0.05 = Peak width at 5% high

F = Leading edge of the peak

Theoretical Plates:

The number of Theoretical Plate represents the column efficiency. It should meet the value given in the monograph. It can be calculated by the following formula:

n = 16(t)²   or  5.54x (t)²

      (W)²           (W_1/2)²

Capacity factor:

K= t – 1

      t_α

t = Retention time of second peak (active)

t_α = Retention time of first peak (impurity)