Use of amino acids to enhance signal in mass spectral analyses

A method of enhancing a mass spectral signal, comprising:

• contacting a sample to a separation column under conditions that permit sample components to bind to a substrate;
• applying a first mobile phase gradient to the separation column, wherein the first mobile phase gradient comprises trifluoroacetic acid (TFA) and a small molecule additive or formic acid (FA) and a first small molecule additive, wherein the first small molecule additive is selected from glycine, alanine, serine, valine, N-acetyl glycine, methionine, β-alanine, aspartic acid, or N-methyl glycine;
• applying a second mobile phase gradient to the separation column, wherein the second mobile phase gradient comprises TFA in acetonitrile (ACN) and a small molecule additive or FA in ACN and a second small molecule additive, wherein the second small molecule additive is selected from glycine, alanine, serine, valine, N-acetyl glycine, methionine, β-alanine, aspartic acid, or N-methyl glycine;
• and
• performing mass spectrometric analysis on eluted sample components, wherein separation between sample components on the separation column is not increased by addition of the small molecule additives in the mobile phase.