Why do BPX columns have low bleed?


SGE substitutes some of the oxygen with the aromatic ‘benzene’ into the polymer backbone, known as the silphenylene unit. The aromatic ring acts as an ‘energy sink. ’ As the column is heated in the GC, the vibrational and rotational energies increase. The aromatic ring helps disperse this energy, thus preventing phase breakdown.

Feature: Silphenylene modified polysiloxane backbone

Benefit: Restricts degradation pathways

  • Phase operating at high temperatures (not necessarily maximum operating temperature)
  • Exposure to oxygen in the carrier gas at elevated temperatures
  • Reactive compounds injected onto the column

The polysiloxane chain breaks down to form very small, stable cyclic polysiloxane ring structures, which cause the rise in the baseline of your chromatogram (column bleed).

 

BPX Technology limits this process

The aromatic ring restricts the formation of these ring structures, therefore reducing column bleed, and allowing the phase to operate at much higher temperatures before column bleed becomes a problem.


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