Versatile Diol Columns for Normal Phase, Reversed Phase, ANP, and SFC
Cogent Diol™ and Cogent NP™ Diol HPLC columns offer exceptional versatility for laboratories performing normal‑phase (NP), reversed‑phase (RP), aqueous normal‑phase (ANP), and supercritical fluid chromatography (SFC). Diol phases are valued for their balanced polarity, making them suitable for a wide range of compounds, including highly acidic and nitrogen‑containing analytes.
Diol stationary phases are less polar than bare silica but more polar than hydrocarbon phases such as C18, providing unique selectivity and robust performance across diverse chromatographic conditions.
Why Choose Diol HPLC Columns?
Diol columns are commonly selected as a more robust alternative to unmodified silica. The diol functional group protects the underlying silica surface, improving column durability while maintaining predictable retention behavior.
Key advantages of diol phases include:
Compatibility with the full range of HPLC solvents
Use from hexane (non‑polar) to water (very polar)
Excellent performance in normal phase and SFC
Suitable replacement for bare silica with modified selectivity
Increased robustness compared to unmodified silica columns
Cogent Diol™ HPLC Columns (TYPE‑C™ Silica)
Cogent Diol™ HPLC columns are manufactured using TYPE‑C™ silica, making them distinctly different from conventional diol phases. This advanced silica hydride surface chemistry provides exceptional robustness and unique selectivity not achievable with traditional silica‑based diol columns.
These columns are suitable for:
Reversed‑phase (RP) HPLC
Normal‑phase (NP) HPLC
Aqueous normal‑phase (ANP / HILIC) HPLC
The TYPE‑C™ diol phase enables broader method flexibility and enhanced stability, especially in challenging solvent systems.
Key benefits of Cogent Diol™ (TYPE‑C™):
Unique silica hydride‑based diol phase
Broad solvent compatibility
Highly robust surface chemistry
Flexible use across RP, NP, and ANP / HILIC methods
Distinct selectivity compared to traditional diol columns
Cogent NP™ Diol HPLC Columns
Cogent NP™ Diol HPLC columns are designed specifically for normal‑phase HPLC and are excellent alternate columns for USP® and in‑house pharmaceutical methods. These columns are made using the same type‑B, high‑purity silica as Cogent RP™ HPLC columns and are packed in non‑polar solvents, allowing immediate use in NP methods right out of the box.
Available particle sizes include:
3 µm
5 µm
10 µm
These characteristics make Cogent NP™ Diol columns a reliable choice for regulated and routine analytical environments.
Key benefits of Cogent NP™ Diol:
Optimized for normal‑phase HPLC
Made with type‑B, high‑purity silica
Packed in non‑polar solvents for immediate NP use
Suitable for USP® and legacy methods
Available in multiple particle sizes
Typical Applications
Normal‑phase and reversed‑phase HPLC
Aqueous normal‑phase (ANP) separations
Supercritical fluid chromatography (SFC)
Highly acidic compounds
Nitrogenous compounds
Pharmaceutical and USP methods
Replacement of bare silica columns
Column Protection Recommendation
Important: MICROSOLV technical support strongly recommends using the Cogent column filter, which is included with each column, whenever possible. Column filters help protect against particulates, extend column life, and maintain consistent chromatographic performance.
👉 Learn more about the Cogent column filter for HPLC column protection
