PEEK Tubing: What It Is and the Different Types

Polyetheretherketone (PEEK) tubing is a high-performance polymer widely used in chromatography applications. Known for its mechanical strength, flexibility, and resistance to harsh solvents, PEEK has become the go-to alternative to stainless steel tubing in many analytical and preparative HPLC systems. Its biocompatibility and smooth internal surface help ensure stable flow rates, minimal sample interaction, and superior chromatographic performance.

What Is PEEK Tubing?

PEEK tubing is manufactured from a semi-crystalline thermoplastic polymer designed to withstand the chemical and physical stresses of HPLC use. It combines high tensile strength with exceptional solvent resistance, maintaining structural integrity under pressures up to approximately 10,000 psi. Its broad pH tolerance (0–14) makes it compatible with a wide range of mobile phases, while its smooth bore minimizes turbulence compared to metal tubing of similar dimensions.

Among polymer tubing materials, PEEK is also one of the least permeable to gases, ensuring consistent performance during long analytical runs. This makes it ideal for transferring solvents and samples in high-precision applications such as bioanalysis, proteomics, and pharmaceutical R&D.

How To Cut PEEK Tubing Correctly

One of PEEK’s main advantages is that it can easily be cut to length in the lab without specialized machining tools. For best results, use a dedicated PEEK tubing cutter—such as the IDEX model—to produce a clean, burr-free, 90° cut. Proper cutting ensures reliable, leak-free HPLC connections and consistent flow characteristics.

Factory-supplied tubing lengths (such as 5 ft) are typically rough cut, so a short trimming cut should always be made before use. Tubing cutters feature guide holes to maintain straight alignment, reducing the risk of irregular edges that could compromise sealing or connection performance.

When Should PEEK Tubing Be Avoided?

While PEEK is highly resistant to most solvents, there are exceptions where degradation or swelling can occur. Avoid using PEEK tubing with the following chemicals:

• Strong acids: Nitric acid, sulfuric acid, and halogenated acids such as hydrofluoric or hydrobromic acid
• Swelling solvents: Methylene chloride, tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), and high concentrations of acetonitrile

Hydrochloric acid is generally safe for most HPLC applications, but when in doubt, consult chemical compatibility charts or contact Chrom Tech for guidance before use.

Other Types of Polymer Tubing for Chromatography

While PEEK is one of the most versatile materials available, several other fluoropolymer options are also popular in chromatography workflows. Each offers unique advantages depending on your pressure, solvent, and application requirements.

DuPont® FEP Fluoropolymer Tubing

FEP (fluorinated ethylene propylene) tubing is chemically inert, translucent, and easy to cut—ideal for low-pressure connections and solvent transfer lines. Its flexibility and clarity make it suitable for monitoring liquid flow between solvent reservoirs and HPLC pumps in general analytical applications.

ETFE Tubing

ETFE (ethylene tetrafluoroethylene) tubing provides higher pressure tolerance than PTFE, FEP, or PFA and is particularly suited for aqueous mobile phases. Its rigidity helps prevent inner diameter collapse, offering enhanced dimensional stability and reduced gas permeability—making it ideal for high-pressure or semi-preparative systems.

DuPont® PFA Tubing

PFA (perfluoroalkoxy alkane) tubing combines excellent chemical resistance with a smoother internal surface than PTFE, enhancing flow consistency and transparency. It’s an excellent choice for aggressive solvent applications where purity and chemical inertness are critical.

Summary

PEEK tubing’s combination of flexibility, chemical resistance, and pressure tolerance makes it an essential component in modern chromatography systems. Whether you’re transferring solvents, connecting pump modules, or building fluidic systems, Chrom Tech provides high-quality PEEK tubing and cutters to help you maintain peak performance and reliability in your HPLC setup.

For more information on tubing compatibility or selecting the right materials for your system, contact our technical support team.