I have a problem. I have purified a protein with method A and then B. After method A I have a protein concentration of 20 mg/ml and after method B a concentration of 18 mg/ml. Method B is dialysis and my sample was diluted, so the volume went from 5 mL (A) to 6 mL (B).
When I present my total amount of protein at these stages I have a higher amount of protein after step B (108 mg) than after step A (100 mg), which is ridiculous, just because of the dilution.
How should I think around this and present this data in my purification table? I know that there can't be more protein after the second step. Should I just calculate the amount of protein after step B, with the volume of step A? Since I know I haven't lost or gained any proteins during the dialysis, I have only gained more buffer which gives me a lower protein concentration.
Please, any advice is valuable to me! Thanks