No-Ox Tubing

• Low permeability prevents "re-gassing"
• Excellent chemical resistance

Most HPLC installations use PTFE tubing for internal low-pressure transfer lines, since PTFE is easy to use and extremely chemically inert. However, PTFE- and PTFE-like polymers have micro pores which allow gases to diffuse freely, to the extent that solvent degassers are often based on that property – gases dissolved in solvents are removed by diffusion when a vacuum is applied on the outside of the tubing. A contrary "re-gassing" effect occurs when degassed solvent passes through PTFE tubing with standard air pressure on the outside – gases diffuse through the PTFE tubing back into the newly (and expensively!) degassed solvent.

To solve this problem, we co-extrude FEP tubing and PVDF tubing to create No-Ox tubing, which is essentially FEP tubing coated on the outside with PVDF tubing. The FEP contributes excellent chemical resistance, while the very tight polymer structure of the PVDF ensures that the degassed solvent will stay degassed until it reaches the HPLC pump.

NOTE: PVDF is not very chemically resistant, but the PVDF layer can easily be stripped from the FEP with a VICI Jour Clean-Cutter or a razor blade so that only FEP contacts the solvent in the solvent reservoir. A special KEL-F tubing insert (P/N 6141) prevents solvent from contacting the PVDF layer at the tubing end in the valve port. The ferrule fits into the ID of the tubing and seals against the bottom of the port.

1/8" OD No-Ox Tubing
Tolerances: OD and ID: ± 0.05 mm (.002)