Add methanol at a concentration of 2 mL/g tissue.
Homogenize (in an ice bath, preferentially).
Centrifuge at 10,000 G for 10 min (at 4ºC, preferentially).
Inject the collected supernatant.
Note: If the concentration is too high, add the same volume of carrier solution to the supernatant.

The life span of the precolumn is about 100 injections of denatured protein samples taken from blood serum, plasma, or tissue.