Your first step in developing a sample preparation procedure should be supported liquid extraction (SLE); if your samples do not require extensive treatment, SLE cleanup is a quick, efficient, and fully automatable solution.

Faster and easier than SPE and liquid-liquid extraction: just load, wait 5 minutes, then elute.
Effective removal of proteins, phospholipids, and salts.
Quick concentration step increases sensitivity.
Easy to automate for high-throughput laboratories.
Suitable for a wide range of sample matrices and analyte pKa values.