24 Oct

HPLC Chromatography: Polar Compounds

Separation of polar compounds require the chromatographic researcher to keep on hand many different types of HPLC columns including reverse phase, normal phase, cation exchange, anion exchange, ion exclusion and perhaps HILIC. All of these columns could be replaced by two Sielc Obelisc™ columns.  The chemical modifications of the silica pores in the Obelisc columns allow the silica pores to change their charge properties in response to the changes in the mobile phase. The Obelisc R has long hydrophobic chains with a cation group near the silica surface and an anion group on the free end. The Obelisc N has a long hydrophilic chain with an anion group near the silica surface and a cation group on the free end.  These chemical modifications of the pores allow for a very different environment within the silica pore than in the mobile phase.  Changes the buffer strength, pH and organic properties of the mobile phase cause conformational changes in the hydrophobic/hydrophilic chains as well as changes in degree of ionization and charge distribution; these changes allow for very versatile selectivity adjustments.  Mass spec, low UV (<220 nm), and ELSD compatible mobile phases can be used with the Obelisc columns facilitating much simpler method development.  The Obelisc columns are compatible with low concentration buffers for preparative work.

Robin Robin