1. The problem statement, all variables and given/known data A purified protein fraction containing buffer with salt can be desalted by one of the following techniques: (1) Gel filtration chromatography (3) Paper chromatography (2) Affinity chromatography (4) Thin layer chromatography 2. The attempt at a solution Well, the analyte contains salt (possible inorganic so the particles, ions will be small enough as compared to a protein) and protein (a large one) so SEC or gel filtration looks perfect. But there's affinity chromatography too. Two things come to my mind: 1.having an antibody or enzyme in the stationary phase will definitely work at holding back the proteins 2. but there may be some non specific polar interactions between the protein and the ions, so... (1) 's the right one?