Wide range of silica phases (unbonded Silica, C18, C18 AQ, C4) and particle sizes (5-15μm) Easy scalability thanks to multiple dimensions (4.6-70mm ID; 150/ 250mm lengths) C18 is the most popular nonpolar phase for prep HPLC separations C18 AQ is stabilized for polar to medium polar compounds in a high water environment C4 is designed for high molecular weight compounds (>2000 Da) like peptides and proteins Silica is used for high and medium polar compounds and organic solvents 70mm ID columns for large scale purification (up to 85g for Silica and 8.5g for C18)