The key difference between cytosol and s9 fraction is that cytosol is a liquid phase which comprises of structural components of a cell apart from the nucleus while s9 fraction is the supernatant fraction obtained from an organ homogenate by the low-speed centrifugation in a suitable medium.
Cytosol and S9 fraction are two components related to cells. The cytosol is the fluid in which the cell organelles are suspended. In simple words, it is the liquid phase found inside the plasma membrane of a cell. S9 fraction is the supernatant obtained from the low-speed centrifugation of a tissue or organ homogenate. It is useful in biological assays in order to measure the metabolism of drugs and other xenobiotics.
