Nanjing Runze Fluid Control Equipment Co., LTD.
Nanjing Runze Fluid Control Equipment Co., LTD.
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How to Choose Peek Fittings for Liquid Chromatography

Peek Polymers

PEEK polymers and their composite high-performance plastics have been widely used in chromatography columns, chromatography analysis, chromatography preparation, flow path fluids, liquid seals and other related equipment because of their high temperature resistance, corrosion resistance, self-lubrication, wear resistance, high strength, high dimensional stability, hydrolysis resistance, and light weight.

High performance thermoplastic material, 30% carbon fiber reinforced polyacrylate ketone (PEEK), meets FDA food contact standards for higher strength and stiffness applications in static or dynamic systems. Good wear resistance, low coefficient of friction, low coefficient of thermal expansion, and chemical resistance.

The liquid chromatography (LC) instrument portfolio includes analytical HPLC and UHPLC systems to meet any separation challenge from simple to complex samples; application-specific HPLC and UHPLC systems for applications such as 2D-LC and dual LC; and nanoflow, capillary, and microflow UHPLC systems for high-sensitivity proteomics, metabolomics, and intact protein analysis.

Typical product forms are: PEEK hand tight fittings, PEEK capillaries, and the big feature of stainless steel fittings is that they are pressure resistant and chemically stable.

PEEK connectors are suitable for use on any manufacturer's instruments and columns for wider applicability and usually do not have the mismatch of connectors mentioned above.


  • No change in tube diameter, no effect on flow rate, more stable flow rate

  • Can be disassembled repeatedly without affecting its sealing

  • Long-term working temperature range -50°C~+150°C

  • Used for standard rigid tubing OD 1.6/2.0/2.5/3.0/3.2mm, easy and

Split connectors are economical and can be used by simply replacing the ferrules.

PEEK Two-piece Hand Tightening Fitting

Peek Two Piece Hand Tightening Fitting

PEEK Flangeless Fitting—two-piece set

Peek Flangeless Fitting Two Piece Set

When replacing columns or connectors, we often encounter poor connections.

The line at the front of the metal ring is too long and the ring does not fit the column well, which can lead to leakage.

If the pipeline at the front of the ring is too short, this can lead to dead volume, resulting in broadened or trailing peaks and poor separation. It is often difficult to think of a mismatched interface when you encounter broad or trailing peaks and poor separation.


Common fitting sizes are available in both metric and imperial sizes.

Available in Both Metric and Imperial

*Note: The imperial sizes are marked with a "-" before the nominal diameter number and a "-" after the number of threads per inch. For example, in "10-32", 10 means 10# nominal diameter and 32 means 32 threads per inch.

PEEK Capillary Tube

PEEK capillary tube is highly recommended to be used with peek fittings.

Brand: RUNZE

Colour: PEEK natural

Operating temperature: maximum CUT 100°C

Product hardness: 90 AS

Applications: bearing, piston, syringe pump, switching valve, etc.


  • 1.6mm OD

  • Biocompatible, inert and easy to cut

  • Ideal for high pressure use

  • PEEK does not react chemically with most solvents and can be used to replace stainless steel tubing in most liquid analysis systems.

  • The very smooth inner surface of PEEK tubing generates less turbulence than metals of similar size, which helps to improve the resolution of sample bands with minimal permeability of PEEK.

Fittings for liquid chromatography normally ask for peek material and stain steel. Peek fittings which resistant to high pressure also circulates on the market, it totally depends on customer needs.

Don't look down upon these fittings, bad connection will directly affect experiment, which result in tailing factor or peak broadening. However, these problems may not be caused by fittings or tubing, peek fittings for liquid chromatography is flexible, easy to intercept, has good chemical solvent inertness, biocompatibility and can be used to replace stainless steel tubing in conventional liquid phase analysis and in ion chromatography and bio-chromatography.

When in usage, first of all, make sure that the tube can pass through the hole inside the peek fitting, secondly, the connection between tube and fittings' hole should not be too loose, basically maintain the state of just passing through, when tightening, make sure that the fitting can lock the tube, in addition, the thread of the fitting should be easily screwed on.