Fractionate samples based on different densities by spinning samples up to 100,000 rpm or ~800,000 x G
Completely remove the solvent from samples through freeze drying with temperatures up to -110°C
Increase the concentration of samples by removing excess solvent via centrifugation with simultaneous reduction of pressure
Replace the buffering solvent of the sample through the use of a stirred cell membrane filter which retains solutes of particular molecular weights
Perform reduction-alkylation and proteolytic digestion (e.g. tryptic digestion) on semi-purified and/or purified protein extracts as preparation for further analysis.