Bonded Phase Chromatography
Definition and meaning of Bonded Phase Chromatography in chemistry.
Bonded phase chromatography (BPC) is a form of liquid chromatography in which the stationary phase is an organic layer covalently attached to a solid support, typically silica particles, rather than a liquid simply coated onto the support surface.
In more detail
Because the stationary phase is chemically anchored through silanization (reaction of surface silanol groups with organochlorosilanes), it cannot be stripped away or dissolved by the mobile phase, giving stable, reproducible columns unlike older liquid-liquid partition systems. Common bonded groups include nonpolar alkyl chains such as octadecylsilyl (C18) or C8 for reversed-phase separations, and polar groups like amino, cyano, or diol for normal-phase work. This durability makes bonded phases the foundation of virtually all modern HPLC and UHPLC, since analyte retention can be tuned simply by changing mobile phase composition rather than replacing the column.
Key facts
| Field | Analytical Chemistry |
|---|---|
| Common support | Silica (SiO2) particles |
| Typical bonded groups | C18 (octadecylsilyl), C8, amino, cyano, diol |
| Attachment chemistry | Silanization forms Si-O-Si-C siloxane bonds |
In reversed-phase HPLC with a C18-bonded silica column, nonpolar analytes partition strongly into the hydrophobic octadecyl chains and elute late with a water/acetonitrile mobile phase, while polar analytes elute earlier.
Frequently asked questions
How does bonded phase chromatography differ from liquid-liquid partition chromatography?
In liquid-liquid partition chromatography the stationary liquid is only physically coated on the support and can slowly bleed into the mobile phase; in BPC the stationary phase is covalently bonded to the support, so it remains fixed and does not dissolve away.
What chemical reaction creates a bonded phase?
Surface silanol (Si-OH) groups on silica react with organochlorosilanes or alkoxysilanes, forming stable siloxane (Si-O-Si-C) linkages that permanently attach the organic functional group to the particle surface.