HPLC Columns

HPLC columns are metal tubes coated with a stationary phase on the inside. They are used to transport analytes and the mobile phase and provide the environment in which separation is achieved.

HPLC columns are metal tubes generally 30 to 300mm in length with internal diameters of 2-5mm coated with a stationary phase on the inside. They are used to transport the analyte and the mobile phase and provide the environment in which separation is achieved. For example, in reversed phase HPLC, where the mobile phase is generally a mixture of polar solvents like acetonitrile and water, the stationary phase is often a silica-based packing covalently bonded with hydrophobic alkyl chains of C8 (octyl group) or C18 (octadecyl group). The reversed phase columns separate analytes on the basis of their hydrophobicity, with the more hydrophobic compounds being retained longer on the column. There are many variations on this theme including normal phase, affinity, ion exchange and size exclusion column stationary phases.