Abstract: The present disclosure relates to methods for separating or isolating a peptide using reverse phase chromatography. The disclosure also relates to methods for calculating or determining the slope S of a peptide, wherein S is defined according to the Linear-Solvent-Strength equation log k=log k0?S*?. Also provided are a set of peptides with known S values suitable for use in the described methods.

Abstract: A composition comprising synthetic peptides for use as a peptide retention standard in liquid chromatography applications is disclosed Said synthetic peptides have a broad range of hydrophobicity while maintaining low variation in their molecular weights The synthetic peptides disclosed consist of the ammo acid sequences LGGGGGGDGSR, LGGGGGGDFR, LLGGGGDFG, LLLGGDFR, LLLLDFR, LLLLLDFR A method of predicting the hydrophobicity of an unknown peptide in liquid chromatography using a composition of peptide retention standards and a method of developing a Universal Hydrophobicity Index (UHI) for the measurement of peptide hydrophobicity in liquid chromatography are also described.

Abstract: The present disclosure relates to methods and systems for analyzing a peptide sample stream from a chromatography column using tandem mass spectroscopy. Analysis of the sample stream during a first time interval is performed in order to identify peptides, such as tryptic peptides, that are contained in the sample stream. Database searching is then performed to identify one or more protein sequences that contain the identified peptide sequence and to identify associated peptide sequences that are contained in the protein sequence that differ from the peptide sequence. The retention time of associated peptides is estimated based on the hydrophobicity of the predicted peptides and by spiking the sample with standard peptides. Information on associated peptides can then be used to configure the mass spectrometer during a second time interval to detect or ignore ions that correspond to the associated peptides.

Abstract: The present disclosure relates to methods for separating or isolating a peptide using reverse phase chromatography. The disclosure also relates to methods for calculating or determining the slope S of a peptide, wherein S is defined according to the Linear-Solvent-Strength equation log k=log k0?S*?. Also provided are a set of peptides with known S values suitable for use in the described methods.

Abstract: A composition comprising synthetic peptides for use as a peptide retention standard in liquid chromatography applications is disclosed Said synthetic peptides have a broad range of hydrophobicity while maintaining low variation in their molecular weights The synthetic peptides disclosed consist of the ammo acid sequences LGGGGGGDGSR, LGGGGGGDFR, LLGGGGDFG, LLLGGDFR, LLLLDFR, LLLLLDFR A method of predicting the hydrophobicity of an unknown peptide in liquid chromatography using a composition of peptide retention standards and a method of developing a Universal Hydrophobicity Index (UHI) for the measurement of peptide hydrophobicity in liquid chromatography are also described