Intrinsic amino acid size parameters from a series of 113 lysine-terminated tryptic digest peptide ions

A study was conducted to analyze cross sections of mixtures of tryptic digest peptide ions established by electrospray ionization using a novel ion mobility/time-of-flight spectrometry method. The peptide mixtures were electrosprayed into the gas phase. The cross sections were found to be dependent on the amino acid structure of each peptide. The reduced cross sections correlated with the fractions of nonpolar or polar aliphatic residues.