Catalog Number - 68518-25P

The 68518‑25P Cogent RP C18 HPLC Column is engineered for maximum separation performance, featuring 5 µm particles and fully double end‑capped C18 bonding to deliver excellent peak shape, reliable retention, and reproducible results.

Manufactured using high‑purity silica with traditional octadecylsilane (C18) bonding, this stationary phase provides:

• Complete end‑capping to minimize silanol interactions

• Improved peak symmetry for polar and basic analytes

• Consistent and robust chromatographic performance

This column is a trusted choice as a primary analytical column, a starting platform for new method development, and a reliable alternate for USP L1 methods using 5 µm phases.

250 mm Length – Maximum Separation & Peak Capacity

• Highest resolving power in the 4.6 mm RP C18 range

• Maximizes peak capacity for highly complex mixtures

• Ideal for closely related analytes and challenging separations

• Provides extended retention for hydrophobic compounds

• Best suited for final method optimization and highest purity separations

This format is selected when shorter columns (50 mm or 100 mm) do not provide adequate resolution or separation.

4.6 mm ID – Standard Analytical Performance

• Industry‑standard HPLC column dimension

• Compatible with all conventional HPLC systems

• Typical flow rate range: ~0.8–1.5 mL/min

• Optimal starting range: ~1.0–1.2 mL/min

Provides:

• Strong detector response

• High reproducibility

• Easy method transfer across laboratories

Flow Rate & System Considerations (4.6 mm ID, 5 µm)

• Suitable for conventional HPLC systems

• Supports a wide range of flow conditions

• Well suited for:

  • Viscous mobile phases

  • Extended gradients

  • Long, high‑resolution analytical runs

Why Choose RP C18 (5 µm)

Robust & Reliable Operation

• Ideal for routine analytical workflows and method development

• Lower backpressure relative to smaller particle sizes

• Suitable for long method lifetimes and consistent results

Reliable Hydrophobic Retention

• Strong reversed‑phase retention for hydrophobic and neutral compounds

• Excellent for long‑chain fatty acids

• Provides greater retention than C8 phases

Method Development & USP Compatibility

• Ideal for new method development and optimization

• Suitable for USP L1 methods using 5 µm particles

• Reliable alternate or replacement column

Cogent RP C18™ Advantages

Fully End‑Capped Surface

• Minimizes secondary interactions

• Improves peak symmetry

• Better performance for basic analytes

High Carbon Load

• Enhanced retention and loading capacity

• Increased method flexibility

Low Column Bleed

• Suitable for sensitive detection methods (UV and LC‑MS)

• Cleaner baselines and improved data quality

High Purity Silica

• Consistent chromatographic performance

• Reduced variability between runs and columns

Typical Applications

• Pharmaceutical and QC analysis

• Hydrophobic and neutral compound separations

• Long‑chain fatty acids

• Complex multi‑component mixtures

• Method development and validation

• USP L1 reversed‑phase workflows

Important Usage Notes

• Compatible with standard HPLC systems

• Ideal for maximum‑resolution analytical workflows

• Best suited when complex separations require high peak capacity

• Optimize method conditions to balance resolution and run time