Calculation of amino acid hydrophilicity indices for retention of peptideson amide, diol and silica columns in normal-phase liquid chromatography

A sei of hydrophilicity parameters in a normal-phase liquid chromatography of peptides is presented in order to clarify the contribution of individual amino acid residues to peptide retention and to predict retention times. T he retention of 100 peptides was studied using normal-phase liquid chromato graphy on amide, diol and silica columns. An acetonitrile-water mixed solut ion containing 0.2% trifluoroacetic acid +0.2% triethylamine was used as th e mobile phase in a linear gradient elution system. The contribution of eac h residue upon retention was calculated by linear multiple regression analy sis. This paper described the contribution valves as "hydrophilicity retent ion coefficients". Using these hydrophilicity retention coefficients, reten tion times could be predicted for peptides of known amino acid content and sequence A set of hydrophilicity retention coefficients on each column was successfully explained by contributions to the degree of retention.