Preparative Column Design Equations

PREPARATIVE COLUMN DESIGN EQUATIONS Optimum Particle Diameter 

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Although, apparently simple, equation (1) has some very significant implications on preparative column design. It is clear from equation (1) that increasing radius and length of the column increases both the maximum sample volume and the maximum sample mass. However, increasing the column length will also increase the columns efficiency (unless the particle diameter is also increased). 

It appears that the equation introduced by Van Deemter is still the simplest and the most reliable for use in general column design. Nevertheless, all the equations helped to further understand the processes that occur in the column. In particular, in addition to describing dispersion, the Kennedy and Knox equation can also be employed to assess the efficiency of the packing procedure used in the preparation of a chromatography column. 

As in the previous chapters on column design, the characteristics of many of the equations discussed in this chapter will be examined employing realistic chromatographic conditions and the typical conditions chosen for a preparative column are given in table 1. 

Procedure Inject the volume of Sample Preparation as designated in the monograph into the column. Determine the concentration of intermediates and side reaction products from the peak areas using the slope, m, and intercept, b, calculated under Calibration by the equation... 

In Sections 4.8 and 4.9, equations (80) and (81) are deduced from the condition when parameters of the device for preparing a selfoc (tumbler (2) and pipe (1) diameters, and wall thickness of pipe (1)) are selected such that after pipe withdrawal after equal shrinkage of monomers, the radius of the central cylinder monomer column (3) and peripheral monomeric circle (4) wall thickness increase by the semi-thickness of the pipe (1) (Figure 46a). In Figime 46b, the volumes of the central and peripheral monomers are designated by V and V4, which fill volumes V2 and F3 that are vacated by taking out pipe (1). Hence, V = F2 and F3 = F4. 

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