Agilent Microsorb C8 100Å columns separate samples by the same hydrophobic interaction mechanism as C18 columns, but with reduced retention. When samples are either too hydrophobic or too polar to chromatograph well on C18, a C8 column is a good alternative. At the other end of the spectrum, some polar compounds exhibit better performance on a C8 column due to better surface coverage of the C8-bonded phase. Samples such as vitamins, antibiotics, and basic drugs are commonly separated using C8 with better symmetry than seen on C18 columns.