Resolution Calculation as per EP

1.0 OBJECTIVE                    

To provide the procedure for calculating the Resolution Calculation as per EP

2.0 SCOPE

This procedure is  for calculating the Resolution Calculation as per EP

3.0 RESPONSIBILITY 

3.1 QC-Chemist 

4.0 ACCOUNTABILITY         

4.1 Executive – Quality control

4.2 Head – Quality control

5.0 PROCEDURE      

5.1 In liquid chromatography, the degree of resolution (Rs) is the most important part of chromatographic separation. Regardless of whether the ultimate purpose of chromatography is quantitative and qualitative analysis or sample preparation, it is achieved on the basis of a certain degree of resolution. The formula for calculating the degree of separation is as follows:

5.2 The resolution (Rs) between peaks of 2 components may be calculated from the expression :

tR₂ > tR₁

5.3 tR1and tR2 = retention times or distances along the baseline from the point of injection to the perpendiculars dropped from the maxima of 2 adjacent peaks,

w₁ and w₂ = peak widths at half-height.

A resolution of greater than 1.5 corresponds to baseline separation.

The expression given above may not be applicable if the peaks are not baseline separated.

tR₂= 11.6

tR₁= 8.4

Wh₁= 1.2

Wh₂=1.25

R= 1.18(11.6-8.4) / (1.2+1.25) =2.60

5.4 The greater the difference in retention time between chromatographic peaks, or the narrower the peak shape, the better the separation (increased resolution). For chromatographic separations, baseline separation helps to obtain accurate quantitative results. Two chromatographic peaks of similar size, with baseline separation corresponding to Rs>1.5.

6.0 ANNEXURES

Nil