<prompt> Protein purification and separation can be done by all except:ChromatographyCentrifugationElectrophoresisDensitometry  <response>: D i.e. DensitometrySDS polyacrylamide gel electrophoresis is method of protein seperation purification on the basis of molecular sizeQ. Whereas electrophoretic mobility of protein in native non-denaturating gel electrophoresis and 2-D gel electrophoresis depends on both charge PI and its mass hydrodynamic size. Densitometry is a method to quantitate protein in tissueQ. 