The retentions of 22 peptides in reversed-phase thin-layer chromatography are determined with methanol, ethanol, or n-propanol as the organic mobile phase. The majority of the peptides show a silanophyl effect: Their flM values first decrease to a minimum and then increase with increasing organic phase concentration. The retention behavior of the peptides is adequately described with a quadratic function; the application of a bilinear function has no additional advantage. Principal component analysis (PCA) proves that each constant in the quadratic function depends on the lipophilicity of the peptides. On the basis of their retention characteristics, the peptides form four distinct groups in the two-dimensional nonlinear map of PC variables: peptides containing a basic amino acid, peptides containing an acidic amino acid, peptides with a ring structure in the amino acid side-chain, and peptides containing uncharged amino acids. Stepwise regression analysis indicates that the organic phase concentration corresponding to the minimum retention of the peptides increases with increasing lipophilicity of the peptides, and decreases with increasing lipophilicity of the organic mobile phase.
ASJC Scopus subject areas
- Analytical Chemistry