The Key Properties of Reversed Phases

Must chromatography be performedroutinely at apH above 8, then it may make more sense to use alternative materials based on polymers, other metal oxides such as Ti02, ZrOj, or pure carbon. 

Frequently, however, the basic compounds in the uncharged state are significantly less stable than in the charged state. This is a well-known observation often noticed in stability studies. In chromatography, sometimes artifacts are observed, which indicate the decomposition of the products, a fact often kept quiet. Therefore, caution should be exercised when working at high pH. Nevertheless, the variation of the pH is, alongside the selection of the stationary phase, the most important optimization parameter for the separation of polar or ionic/ionizable components. 

The properties that essentially influence the selectivity of the reversed phase are hydrophobicity, hydrophobic selectivity, silanophihc activity, shape selectivity, polar selectivity, and metal content. These properties are different for each different support and, therefore, essentially determine the separation. 

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