Understanding the Source of Extra Column Volume

ECV arises from components external to the column, including:

• Injector and detector flow paths
• Tubing length and internal diameter
• Fittings and connectors
• Detector flow cell volume

These components contribute to Extra Column Dispersion (ECD), which broadens peaks and reduces resolution. The effect is amplified with smaller particle columns (e.g., sub-2 µm or core-shell), where system dispersion can easily dominate column efficiency.

Real-World Example

Two chromatograms generated using the same method and column on two different HPLC instruments can show significant differences in peak shape and resolution. This is often due to:

• Older instruments having longer or wider tubing
• Non-optimized flow cells with larger internal volumes
• Poorly cut or mismatched fittings introducing dead volume

Best Practices to Minimize ECV

• Use short, narrow-bore tubing (e.g., 0.007" ID) between the injector, column, and detector.
• Ensure fittings are properly cut, clean, and securely tightened.
• Replace aging or worn components that may introduce dead volume.
• Consult your instrument manufacturer for ECV specifications and optimization guidelines.

Qualification and Measurement

To quantify and monitor ECV in your system, we recommend using one of the Chemical Solutions DIY Qualification Kits™. These kits allows you to:

• Measure system dispersion using traceable standards
• Benchmark performance across instruments
• Ensure compliance with internal or regulatory qualification protocols

The kit is cost-effective, easy to use, and ideal for self-compliance and routine system checks.

📦 Click HERE for the Chemical Solutions PQ and HSQ Kit™ ordering information and images.