Understanding TYPE‑C™ Silica: High‑Purity Silica with Low Metal Content for Superior Chromatography
Cogent TYPE‑C™ silica‑based HPLC columns are engineered to provide the physical advantages of high‑purity Type‑B silica while introducing a unique modification step that fundamentally changes their chromatographic behavior. These attributes deliver significant performance benefits across LC‑MS and HPLC workflows, particularly for polar compounds and analytes sensitive to metal content.
This article explains the composition, manufacturing process, and functional advantages of TYPE‑C™ silica.
High‑Purity Type‑B Silica Foundation
All Cogent TYPE‑C™ columns start with high‑purity, low‑metal Type‑B silica, which provides several key advantages:
- Reduced metal impurities → less unwanted interactions
- Lower surface reactivity → improved peak shape and reproducibility
- Greater chemical and pH stability compared to older Type‑A silica
This ensures a clean, inert base material before further modification.
What Makes TYPE‑C™ Silica Different?
TYPE‑C™ silica undergoes a proprietary surface modification process that transforms it into silica hydride. This process replaces the typical surface silanol groups with Si–H (silicon–hydride) groups.
Why This Matters
- Silica hydride is far less polar than standard silica.
- It does not hold a layer of tightly bound water, unlike conventional silica surfaces.
-
This results in:
- More predictable retention
- Less secondary interaction
- Better compatibility with ANP (Aqueous Normal Phase), RP, and NP modes
The absence of a thick water layer is a defining characteristic of TYPE‑C™ columns and a major contributor to their unique selectivity.
Final Stationary Phase: Silica Hydride + Functional Ligands
After hydride formation, TYPE‑C™ silica is bonded with unique ligands to create different Cogent stationary phases (e.g., Bidentate C18™, Phenyl Hydride™, Diamond Hydride™).
These phases offer:
- Special selectivity not achievable with traditional silica
- Hybrid retention modes (RP + ANP)
- Consistent performance for polar and nonpolar analytes
The result is a stationary phase with both high purity and enhanced functionality.
Advantages of TYPE‑C™ Silica Over Conventional Silica
✔ Low metal content
→ Reduces chelation issues and peak distortion, especially for acidic or metal‑sensitive compounds.
✔ Hydrophobic surface
→ Minimizes water layer formation and improves reproducibility.
✔ Multiple retention mechanisms
→ Supports Aqueous Normal Phase (ANP), Reversed Phase (RP), and traditional Normal Phase (NP).
✔ Improved robustness
→ Better stability, cleaner baselines, and enhanced performance in LC‑MS.
All these properties arise from the engineered silica hydride surface and high‑purity materials used in manufacturing.
Conclusion
Cogent TYPE‑C™ silica combines high‑purity Type‑B silica with hydride surface chemistry to produce a stationary phase that is low in metal content, hydrophobic, and exceptionally versatile.
Its unique structure supports multiple chromatographic modes and reduces unwanted interactions, making it ideal for modern LC‑MS applications and advanced method development.
