How do I calculate hplc resolution values using all the peak pair values below?

Question

Retention Time(min) Width(half)(min)

2.320 0.093

8.924 0.215

11.515 0.246

12.760 0.290

20.028 0.420

Pls help!

Answer 1

The resolution between two peaks a & b in any chromatograph is given by:

Rs = 2 (RTa - RTb) / (Wa + Wb)

where RTs are the retention times and Ws are the widths at the baseline of the peaks. "Acceptable" resolution between two peaks is considered to be Rs > 1.0, and complete baseline resolution has Rs > 1.5. Since widths at half height are given and not baseline widths, all we can do is assume the peaks are of Gaussian distribution, in which the baseline widths are 4x the widths at half height. The resolutions of the first two peaks is then:

Rs = 2 * (8.924 - 2.320) / (4 * 0.093 + 4 * 0.215) = 35.5.

In the same manner, the resolution between the next four peaks are 6.03, 2.53, and 12.53, respectively. All of the peaks are completely resolved.