Reversed-Phase Columns

The use of high performance liquid chromatography (HPLC) for the separation and purification of organic compounds including pharmaceuticals, natural products, food additives, organic chemicals and biologicals, has increased dramatically in the past three decades. This increase is undoubtedly associated with the dramatic improvement in bonding chemistry.

When chromatographic separation is done in a reversed-phase mode, the surface chemistry of the stationary (or bonded) phase has a nonpolar characteristic. The mobile phase is generally polar and the polarity can be achieved by variation of one or more polar organic solvents (such as methanol and acetonitrile) with water. Furthermore, the ability to vary the nonpolar characteristic of the stationary phase provides ground for exibility and the continuous growth of interest in separation using reversed-phase mode. For example, SMT offers many stationary phases with mixed-mode features. In fact, the limiting factor in reversed phase chromatography now depends on the characteristics of the stationary phases procurable. Thus, future advancement in separation science will be governed by the amount of efforts expended on surface modification and materials engineering.