Most Popular Diol Column for Normal‑Phase HPLC and SFC
Scalable from Analytical to Prep | Wide Particle Size Range
Cogent NP™ Diol HPLC columns are MICROSOLV’s most popular diol phase, widely used for normal‑phase (NP) HPLC and supercritical fluid chromatography (SFC). These columns are valued for their robustness, predictable retention, and flexibility across a broad range of solvents and applications, with scalability from analytical to preparative separations.
Diol phases are frequently selected as a more durable alternative to unmodified silica, offering similar usability with enhanced stability and broader solvent compatibility.
Why Choose a Diol Phase for Normal‑Phase HPLC?
Diol stationary phases can be used with the full range of HPLC solvents, but are most commonly applied in normal‑phase HPLC and SFC. Compared to bare silica, diol columns provide:
Improved robustness
Reduced surface activity
Broader solvent compatibility
Predictable retention behavior
Because the diol functional group protects the underlying silica surface, these columns tolerate a wider solvent range—from hexane (non‑polar) to water (very polar)—than unmodified silica.
Although selectivity may differ slightly from bare silica, Cogent NP™ Diol columns are often chosen as a drop‑in replacement for standard NP applications where improved durability and reproducibility are desired.
Fast Equilibration and Gradient‑Friendly Performance
Cogent NP™ Diol columns are not end‑capped, which contributes to:
Faster equilibration than unmodified silica columns
Lower retention, reducing run times
Improved performance for normal‑phase gradient methods
These characteristics make them an excellent choice for laboratories running high‑throughput or gradient‑based NP workflows.
Packed and Ready for Normal‑Phase Use
Each Cogent NP™ Diol column is packed and ready for immediate use in normal‑phase HPLC, eliminating the need for conditioning or solvent exchange before method startup. The columns are available in a wide range of particle sizes, enabling:
Method development and optimization
Routine analytical testing
Scale‑up from analytical to preparative chromatography
They are also fully compatible with SFC methods, expanding their utility beyond traditional HPLC.
Key Features and Benefits
Most popular diol column in the Cogent portfolio
Optimized for normal‑phase HPLC
SFC compatible
Non‑end capped for faster equilibration
Less retentive than unmodified silica
Broad solvent compatibility
More robust than bare silica columns
Available in a wide range of particle sizes
Scalable from analytical to preparative separations
Typical Applications
Normal‑phase HPLC separations
Supercritical fluid chromatography (SFC)
Replacement of unmodified silica columns
Gradient NP methods
Analytical and preparative chromatography
Pharmaceutical and chemical analysis
Additional Resources
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
