PEEK Tubing & Fittings
A complete range of chromatography tubing, fittings, nuts, compression screws and ferrules in PEEK and stainless steel — bioinert, solvent resistant, compatible with 1/16″ and 1/8″ standard tubing, reducing metal ion contamination and system dead volume.
Made from polyether ether ketone (PEEK): bioinert, resistant to organic solvents, and suited to biological samples sensitive to metal ions. A full range of PEEK tubing, fittings, nuts and compression screws for chromatography systems, reducing the risk of metal ion contamination. Compatible with 1/16″ and 1/8″ standard tubing.
Stainless steel and PEEK chromatography fittings, nuts, compression screws and ferrules, compatible with 1/16″ and 1/8″ standard tubing. Covers column end fittings, in-line filters, mixers and other system components, reducing system dead volume and extra-column broadening.
PEEK or Stainless Steel
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| Criterion | PEEK | 316 stainless steel |
|---|---|---|
| Biocompatibility | Bioinert— no metal ion leaching; better recovery for proteins and phosphopeptides | Risk of metal ion leaching and chelation |
| Pressure rating | Typically < 5000 psi (falling with larger bore and higher temperature) | Up to tens of thousands of psi; UHPLC requires steel tubing |
| Installation | Finger-tight, and can be reconnected repeatedly | Once swaged, the ferrule is committed to that fitting |
| Solvent limitations | Attacked by concentrated sulfuric/nitric acid; swells on prolonged contact with THF, DCM or DMSO | Compatible with all common reversed-phase solvents; watch for pitting with halides and high salt |
| Temperature | < 100 °C recommended for continuous use | Wide temperature range |
Tubing bore directly determines extra-column broadening
The tubing volume between column outlet and detector ispure loss — it contributes nothing to the separation yet still broadens peaks. Volume grows with the square of the bore: over the same 30 cm length, 0.010″ tubing holds roughly four times the volume of 0.005″.
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| Internal Diameter | Common color code | Typical use |
|---|---|---|
| 0.005″（0.13 mm） | Red | Post-column connections for UHPLC and narrow-bore columns; minimal broadening, but high flow resistance — keep it short |
| 0.007″（0.18 mm） | Blue | The balanced choice for post-column connections on conventional analytical columns |
| 0.010″（0.25 mm） | Orange | Pre-column, low-demand runs such as pump to injector |
| 0.020″ and above / 1/8″ | Green and others | Preparative and semi-preparative flow paths, waste lines |
Three rules for controlling dead volume: (1) always cut tubing square with a proper tubing cutter — an angled cut leaves a cavity; (2) seat the tubing fully against the bottom of the fitting before tightening, otherwise you create dead volume that cannot be removed; (3) cone depths differ between fitting brands, so re-seat the tubing when changing brands rather than relying on the old ferrule position.