Columns and Stationary Phases

The column is the heart of the chromatographic system and it is the only device where actual separation of the analyte mixture takes place. Detailed discussion of HPLC columns and stationary phases is given in chapter 3. 

Those who prepare and/or manufacture LC columns must use the above methods to limit the effects of eddy diffusion on the chromatographic separations. However, there are practical limitations. Column and stationary-phase particle diameters can only be reduced to points that are compatible with the pressure limitations of the pumps used in chromatographic instruments and the required sample capacities of the columns. The degree of training and experience of those who pack the columns may also limit the quality of the procedure used in packing the column. Nevertheless, most commercial manufactur-... 

This chapter considers gas chromatography in detail, including the columns and stationary phases that are most widely used. Although this chapter is primarily concerned with gas-liquid chromatography, there is a brief discussion of gas-solid chromatography. 

Guidelines for Choosing Chromatographic Columns and Stationary Phases 1105... 

Separation number (SN) is a practical, alternative means of describing the separating capabilities of a capillary column. SN shows the ability of a given column and stationary phase to separate a mixture into its components with a resolution of 1.0 between the peaks. SN is calculated from retention times and peak widths of two consecutive homologous n-alkanes having Z and Z + 1 carbon atoms and indicates the number of component peaks that can be resolved R 1.0) between the two alkanes in a given part of the chromatogram. 

Column and stationary phase New column with the same stationary phase, but better packing ... 

The column is often called the heart of the HPLC separation process, and the availability of stable, high performance stationary phases and columns is critical to the development of mgged, reproducible and robust methods. Modem commercial columns can differ widely among suppliers and these differences can sometimes affect the development process of the desired HPLC method. Specifically, different columns can vary in terms of plate numbers (Af), retention characteristics (X) and resolution (i s). For these reasons, column and stationary phase manufactures have developed technologies to help ensure that these separation materials are produced in a more consistent and reproducible maimer. An excellent reference by Snyder etal. [1] provides a comprehensive overview of modem stationary phases and column technology. 

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