Introduction

Polyether Ether Ketone (PEEK) tubing is widely used in HPLC, UHPLC, LC-MS, biotechnology, and analytical laboratory systems due to its excellent chemical resistance, mechanical strength, and metal-free fluid path characteristics.

When selecting tubing for sensitive analytical applications, laboratories often inquire about manufacturing additives, processing aids, or other materials that could potentially affect sample integrity, extractables, or overall system performance.

Does Virgin PEEK Tubing Contain Additives?

Virgin PEEK tubing is manufactured without performance-enhancing additives, fillers, colorants, reinforcing agents, or other intentional modification materials.

This helps provide:

• Consistent material properties
• Excellent chemical resistance
• Low extractables potential
• Reliable fluid-path performance
• Suitability for analytical laboratory applications

Because no additives are incorporated into the PEEK material itself, the tubing maintains the characteristics associated with virgin PEEK resin.

Considerations Related to PEEK Manufacturing

Although additives are not intentionally incorporated into virgin PEEK tubing, chromatographers should be aware that PEEK resin is manufactured using chemical processes that may involve various production materials.

One example is phosphoric acid, which may be used during PEEK production.  As with many manufactured materials, trace residuals from the production process may be present at very low levels. The significance of such residuals will depend on the sensitivity requirements of the intended analytical application.

For highly sensitive trace-level analyses, laboratories should evaluate material suitability according to their internal validation requirements.

Why PEEK Is Commonly Used in Chromatography

PEEK has become one of the most widely used materials in chromatography because of its unique combination of properties.

Key Advantages

• Broad chemical compatibility
• High mechanical strength
• Metal-free fluid path
• Corrosion resistance
• Low extractables profile
• Compatibility with HPLC, UHPLC, and LC-MS systems
• Excellent pressure tolerance in appropriate tubing dimensions

These characteristics make PEEK suitable for tubing, fittings, ferrules, unions, adapters, and other chromatography components.

Chemical Compatibility Considerations

Although PEEK is highly resistant to many solvents and laboratory chemicals, it is not completely inert under all conditions.  PEEK is not a fluoropolymer , and therefore should not be considered universally resistant to every chemical environment.

Before selecting PEEK tubing, laboratories should evaluate compatibility with:

• Solvents
• Reagents
• Sample matrices
• Cleaning agents
• Elevated temperature conditions

Chemical compatibility should always be confirmed for the specific application.

Applications for Virgin PEEK Tubing

Virgin PEEK tubing is commonly used for:

• HPLC fluid paths
• UHPLC systems
• LC-MS systems
• Biocompatible flow paths
• Pharmaceutical analysis
• Bioanalytical methods
• Sample transfer lines
• Laboratory automation systems

Its combination of purity and chemical resistance makes it a common choice for demanding analytical environments.

Conclusion

Virgin PEEK tubing is manufactured without additives, fillers, or reinforcing materials, helping maintain the chemical resistance and performance characteristics associated with pure PEEK. While PEEK production may involve phosphoric acid during resin manufacturing, the tubing itself does not contain intentionally added modifiers. As with any chromatography material, chemical compatibility should be evaluated for the specific solvents and operating conditions involved in the application.