A method of enhancing a mass spectral signal is disclosed. The method can include contacting a sample to a separation column under conditions that permit sample components to bind to the substrate; applying a first mobile gradient to the separation column, wherein the first mobile phase gradient comprises trifluoroacetic acid (TFA) and a small molecule additive (e.g., an amino acid) or formic acid (FA) and a small molecule additive (e.g., an amino acid); applying a second mobile gradient to the separation column, wherein the second mobile phase gradient comprises TFA in acetonitrile (ACN) and a small molecule additive (e.g., an amino acid) or formic acid (FA) in ACN and a small molecule additive (e.g., an amino acid); and performing mass spectrometric analysis on eluted sample components.