Which Column Will Affect the Separation

Here we need to consider which column might be the best one with which to start depending on our analytes of interest. For example, is the column going to need to be nonpolar in natme and, if so, would a Cg suffice or is a Cjg required The following parameters should be carefully considered. 

This choice will depend on the nature of the analytes that are being separated and the mechanism required to maximise the separation (see Chapter 4). For example, if the analytes are particularly acidic in nature, it may be necessary to choose ion exchange chromatography. If the analytes are nonpolar in nature, then reversed phase HPLC might be a suitable choice. 

Column selectivity is based on the affinity of the analytes of interest and the stationary phase. If we take reversed phase chromatography as an example, we know from Chapter 4 that the interaction is based on the hydrophobicity of both the stationary phase and the analytes of interest. Ihe more hydro-phobic the analyte is, the more it will be retained on a hydrophobic column. Similarly, the more hydrophobic the column is, the more it will retain hydro-phobic analytes. 

Column Chemistry Column Packing Type pH Range Application 

Bulky silane group with Polar embedded 2-8 Basic analytes—reduced 

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