Question

1. On a chromatographic column one meter in length, operating with an efficiency of 10,000 plates, the retention time of ?-chlorestne and ?-chlorestne are 4025 and 4100 seconds respectively. If these two compounds are to be separated with baseline resolution, can the desired separation be accomplished using this one meter column? The dead time of the column is 480 seconds.

Answer 1

Given:

N =Number of theorotical plates = 10000 plates

t_rA = retention time of A-Chlorestne = 4025 seconds

t_rB = reention time of B-chlorestne = 4100 seconds

t_o = dead time of the column = 480 seconds

Here in this problem we have to check foe desired separation can be achieved by using one meter column.

So first we find the peak width at half height by formula given as,

  

for A-chlorestne = 161 seconds and = 164 seconds

The degree of separation between two compounds can be calculated by formula as,

On substituting the values we get,

In general we want according to standard results,

We have one more standard formula as,

Here we can say from the formula that the   

Let R₁= 0.461 , R₂ = 1.5 and  N₁ = 10000,   

Solving the above equation, we get

Height equivalent to theorotical plate is given by

So initially using 10000 plates and length one meter we get the H= 1 * 10^-4 m

Now, we know that   .....Ans

So desired separation cannot be achieved by one meter column. For this we will need column of height to achieve desired separation.