Improved intact peptide and protein quantitation by LC-MS: Battling the deleterious effects of analyte adsorption.

Peptide and protein quantitation by liquid chromatography-mass spectrometry relies on the assumption of linear signal response with concentration. At low concentrations, analyte adsorption to pipette tips, sample vials and equipment can have significant deleterious effects on signal response. Meanwhile at high concentrations, linearity breaks down due to competitive ionization, signal suppression, and the formation of peptide or protein multimers.