The Column Length and Analysis Time

By using exactly the same procedures as those used in the design of packed columns the same equations can be derived for the column length and the analysis time. Namely, 

Where (k 2) is the last eluted peak of the mixture and the other various symbols have the meanings previously ascribed to them. 

Employing Equation (3) and the data given in table 1, the optimum column length was calculated for the preparative separation of a solute where the separation ratio of the critical pair ranged from 1.01 to 1.50, again at inlet pressures of 1,10,100,1,000 and 10,000 p.s.i. The results obtained are shown in figure 2 

Graph of Optimum Column Length against Separation Ratio 

It is seen from figure 2 that the optimum column length ranges from over 500 meters to a fraction of a millimeter. It is also obvious that there must be further limitations placed on the design of the column to ensure its practical use. A preparative column less than 5 cm in length would be very difficult to pack as would a preparative column that had a length greater 

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