Patent ID: 8620595

Claim:
A method for separating or isolating a peptide with a known amino acid sequence from a sample, the method comprising: (a) providing a sample comprising the peptide; (b) determining for the peptide a peptide charge, a peptide length, a hydrophobicity of the peptide, a distribution of hydrophobic amino acids within the peptide and a number of occurrences of each amino acid in the peptide; (c) using the function: S=C 1* Z C2 +C 3* N C4 +C 5* HI C6 +C 7 /Z+C 8 /N+C 9 /HI+C 10* ZN+C 11* ZHI+C 12* NHI+C 13* Z*N*HI C14 +B+S aa +SSSF; to determine a slope S for the peptide, wherein the slope S represents a change in retention of the peptide in a reverse phase chromatography column with respect to a change in a mobile phase gradient slope during reverse-phase chromatographic separation and where N is the peptide length, Z is the peptide charge, HI is the hydrophobicity of the peptide, S aa is calculated based on the number of occurrences of each amino acid in the peptide, SSSF is calculated based on the sequence of the peptide and where constant B and coefficients C1 to C14 are empirically determined; (d) determining a retention time for the peptide in a reverse phase chromatography column based on the slope S; (e) introducing the sample into the reverse phase chromatography column with a mobile phase; and (f) collecting an eluent out of the column at the retention time determined in (c), wherein the eluent contains the peptide.