Dead-space volume chromatography

Columns for gel permeation chromatography must have both a minimal dead space volume at the outlet, to prevent broadening of the zones developed during the separation, and a suitable bed support, e.g. nylon mesh, which will retain the gel without becoming blocked. The length of the column affects the resolution,... 

The retention factor, k, is the basic value in chromatography, and is related to the void volume (dead volume). The void volume is the space inside the column, where no retention of solutes has occurred and can be measured on a chromatogram, as shown in Figure 1.3. The void volume is about half the total volume of the column when it is packed with porous stationary phase materials. In practice, the effective void experienced by the analyte is smaller because the molecular mass of the analyte is usually much greater than that of the eluent molecule. In a model of porous stationary phase material, the pores can be represented as V-shape valleys (Figure 3.8), where region a is a support, such as... 

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