Catalog Number - 68518-30P-3.9

The 68518‑30P‑3.9 Cogent RP C18 HPLC Column is designed for maximum separation performance and method compatibility, featuring 5 µm particles and fully double end‑capped C18 bonding to deliver reliable retention, excellent peak shape, 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 durable chromatographic performance

This column is especially suited for legacy chromatographic methods and as an alternate for USP L1 methods requiring specific column dimensions.

300 mm Length – Maximum Separation & Retention

• Provides extended separation length for maximum resolution

• Maximizes peak capacity for highly complex mixtures

• Ideal for challenging separations and closely related analytes

• Offers longer retention for hydrophobic compounds

• Best suited for final method validation and high‑purity separations

This format is used when shorter column lengths cannot meet resolution or retention requirements.

3.9 mm ID – Legacy Method Compatibility

• Matches traditional analytical column dimensions used in older HPLC methods

• Commonly specified in legacy USP L1 methods and validated procedures

• Typical flow rate range: ~0.8–1.3 mL/min

• Optimal starting range: ~0.9–1.1 mL/min

Benefits:

• Maintains method consistency without revalidation

• Ensures compatibility with established protocols

• Provides a bridge between modern columns and legacy systems

Flow Rate & System Considerations (3.9 mm ID, 5 µm)

• Compatible with standard HPLC systems

• Supports longer analytical runs and extended gradients

• Well suited for:

  • Legacy method transfer

  • Validation and compliance workflows

  • Complex, high‑resolution separations

Why Choose RP C18 (5 µm)

Robust & Reliable Operation

• Ideal for established methods and routine analysis

• Lower backpressure relative to smaller particle sizes

• Suitable for consistent, repeatable performance over time

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 Compatibility & USP Alignment

• Ideal for USP L1 method substitution

• Supports legacy method requirements and validation protocols

• Reliable platform for method transfer and consistency

Cogent RP C18™ Advantages

Fully End‑Capped Surface

• Minimizes secondary interactions

• Improves peak symmetry

• Better performance for basic analytes

High Purity Silica

• Consistent chromatographic behavior

• Reduced variability across runs and batches

Durable & Cost‑Efficient

• Long column lifetime

• Reduced system wear

• Lower maintenance requirements

Typical Applications

• USP L1 legacy method replacement

• Pharmaceutical QC and validation

• Hydrophobic and neutral compound separations

• Long‑chain fatty acid analysis

• Complex multi‑component mixtures

• Method transfer and regulatory workflows

Important Usage Notes

• Designed for legacy method compatibility (3.9 mm ID)

• Compatible with standard HPLC systems

• Ideal for maximum separation and retention requirements

• Use when method fidelity and regulatory compliance are critical