Salt required in SEC?

[separation]

Am trying to eliminate the use of NaCl in SEC. If the solvent is adequently buffered (>100mM NaPO4), does the gel require such high levels of NaCl (>100mM) for stability, swelling, etc for the proteins to resolve?

Thanks

[tom jupille]

Depends on the "gel". Many polymer-based packings will shrink/swell significantly with changes in ionic strength. Some polymer-based and most silica-based packings (designed for HPLC use) have sufficient structural rigidity that salt is not required for that purpose. It may still be necessary to mitigate secondary interactions (ion exchange / ion exclusion).

Check with the stationary phase manufacturer for their specific recommendations for a particular material.