How do you pretreat a solid sample? (Pretreatment series)

A solid sample is homogenized according to the properties of target analytes.  Organic analytes require homogenization in organic solvents and a SPE cleanup using a normal phase sorbent such as silica. 

For water soluble analytes, homogenization can be done in water-organic miscible solvents such as methanol and the subsequent cleanup is done on a reversed phase SPE sorbent.

Homogenization can be done by blending or grounding crude sample (sample can also be freeze dried) in the appropriate solvent.  After sonication or mixing, the sample is centrifuge and the supernatant is evaporated down and reconstituted in the correct loading solvent for the corresponding SPE method.