Effect of Conformation on Retention

Larger flexible molecules may fold on their way through the HPLC column, and thus display an unpredictable lipophilicity behavior. For example, a conformational effect can play a role when a series of homologs with varying chain length is studied. An interesting example of this conformation-dependent behavior has recently been found in a series a benzylamines [27]. Log kw values increase from methyl to butyl, but then drop again for the pentyl homolog.

Significant conformational effects must be expected for macromolecules, such as peptides and nucleic acids. This folding process may be slow, giving rise to peak broadening.

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