Peak separation in gas chromatography

The peak separation will depend on the nature of the two components to be separated. The more different are the distribution constants K and K, for the components, the more different are their retention times tR, as seen in rel. (6). The separation factor a is commonly used to characterize the separation, where 

A good separation is attained for a large separation factor (by convention a 1) when the ki kj product is as close as possible to unity. An evaluation of how well two peaks are separated can be obtained from the chromatogram using the formula  

The two peaks are considered base to base separated when Rs 1, which corresponds to A tR = W(, (when Wbi is assumed equal to Wb2)- Therefore, a good separation will be achieved when 

The resolution Rs depends on the capacity factors ki, separation factor a and the number of theoretical plates n. Assuming that Wbi = Wb2 and noticing that 

The separation of two components on a chromatographic column will be better when n Is higher or Hmin is lower. 

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Figure 5.2.6. The factor depending on k in the expression of 2-- Peak separation in gas chromatography.

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