High-performance liquid chromatography of amino acids, peptides and proteins. CX. Principal component analysis of four sets of group retention coefficients derived from reversed-phase high-performance liquid chromatography of peptides

Principal component analysis procedures have been used to further characteristise peptide retention behaviour in reversed-phase (RP) high-performance liquid chromatography. In particular, the analysis was performed with four new scales of group retention coefficients (GRCs) in conjunction with fourteen physicochemical descriptors of the side chain functionalities of the twenty naturally occurring amino acids. The results demonstrate a negative correlation between GRCs derived from peptide retention data with RP-C18 or RP-C8 stationary phases and aqueous trifluoroacetic acid-acetonitrile solvents and amino acid parameters which describe electronic characteristics. Conversely, there was a positive correlation between GRCs derived from peptide retention data with a RP-C18 stationary phase and aqueous trifluoroacetic acid-acetonitrile-2-propanol mixtures and amino acid parameters related to steric and volume characteristics. These results are interpreted in terms of the solvophobic theory. The relevance of quantitative structure-retention relationships to the mechanistic basis of peptide and protein interactions with chromatographic surfaces is discussed.