There are significant differences between HILIC columns and Cogent TYPE-C™ Silica Hydride columns, though both can separate polar compounds. Here are the key points:

Similarities:
Both HILIC and Cogent TYPE-C™ columns retain polar compounds when using mobile phases with high organic content (>70%). Each operates on principles related to normal-phase chromatography—HILIC is classified as “Hydrophilic Interaction Chromatography,” while Cogent columns use Aqueous Normal Phase (ANP). Both can retain analytes that reversed-phase columns cannot.

Differences:

• Stationary Phase Polarity: HILIC phases are highly polar, whereas TYPE-C™ phases are relatively non-polar.
• Retention Profile: HILIC columns do not retain non-polar compounds, while Cogent columns can retain both polar and many non-polar compounds—sometimes in the same gradient or isocratic run.
• Mechanism:
  • HILIC relies on a hydration layer on the silica surface. Polar analytes partition into this layer and interact with silanols beneath it. This requires careful equilibration for reproducibility.
  • Cogent TYPE-C™ columns lack significant silanols and hydration shells. Retention of polar compounds occurs via adsorption on the silica hydride surface, while bonded phases allow non-polar retention. This design enables rapid equilibration and fast gradient changes.
• Versatility: HILIC columns are limited to HILIC mode. Cogent TYPE-C™ columns can switch seamlessly between ANP, RP, and traditional Normal Phase (using non-polar solvents like hexane) without hysteresis.

This flexibility makes Cogent TYPE-C™ columns uniquely efficient for complex separations. Additional features and benefits are detailed in other Knowledge Base article s.

       HILIC Phases have a Water Shell        Cogent TYPE-C Silica has no Water Shell