This Application Note describes an improved method for protein identification with two-dimensional nano LC/MS, which utilizes the elution of digest peptides from a strong cation exchange column by an injected salt step gradient of increasing salt concentration with a subsequent reversed phase separation. However, in this approach the ion exchange chromatography does not produce its full performance. To improve the SCX chromatography performance a new method was developed, which works with a semi-continuous pumped salt gradient. This Application Note describes the improved method for two-dimensional nano LC/MS. To show the full performance of the method a complex tryptic digest of the yeast proteome was analyzed. The results obtained with the developed method are compared to the formerly used injection method as well as to an off-line 2D LC method.
The document introduces an improved method for two-dimensional nano LC/MS that utilizes a semi-continuous pumped salt gradient to optimize strong cation exchange (SCX) chromatography performance. This approach addresses limitations of traditional injected salt plugs, such as poor peptide distribution and ionization suppression, by keeping the SCX column near equilibrium.
The improved method uses a semi-continuous pumped salt gradient instead of injected salt solution plugs to optimize SCX chromatography performance.
This document describes an improved method for two-dimensional nano LC/MS that works with a semi-continuous pumped salt gradient to improve SCX chromatography performance.
A complex tryptic digest of the yeast proteome was analyzed to show the full performance of the developed method.
The salt gradient begins at 0% to 2.5% of a 500 mM NaCl solution for the first step.