Desalting and buffer exchange are both separation processes carried out using size exclusion chromatography (SEC), also known as gel filtration chromatography. There are a few significant differences between the two processes.
Desalting:
- Involves removal of salts from a sample
- Is achieved by first equilibrating the chromatography column with water
Buffer Exchange:
- Involves replacing one set of buffer salts with another
- Is accomplished by first equilibrating the column resin with the desired buffer for the sample
In both cases, the solution with which the column is pre-equilibrated replaces the buffer constituents that carry the sample into the column.