Hi, Thank you Aradne,

Previously I studied the paper, but in most of research papers, authors have used ammonium sulfate. Thank you for your reply,

Yes, you can use it but mostly used is ammonium sulfate due to its high solubility and it is cheap. For concentration of NaCL , if it was not optimized , it better to take differents concentration , just to optimize it.

On predicting the pH of a pure (NH4)2SO4 aq. sol.; see: https://www.researchgate.net/post/What-is-the-difference-between-using-ammonium-sulfate-and-using-sodium-sulphate-in-protein-ppt-and-seperation