Update on gas uptake through tubing walls

The free laboratory magazine EuroLab reported in its October 2025 issue about an investigation of tubing gas permeability performed at Biotech Fluidics. This study, featured in the magazine’s section for analytical & lab equipment, was composed by Dr. Magda Nyström and Anders Grahn at Biotech Fluidics, together with liquid chromatography expert Dr. Tobias Jonsson at Diduco.

Comparing gas permeability for different types of tubing

The article describes an experimental setup constructed to compare oxygen gas permeability through different transfer tubing in precision fluidic systems. The reason for this study is that high influx of gases into the liquid flow line could even nullify the benefits of an inline degasser. Ultimately this re-gassing could lead to poor precision and low accuracy in the system output due to bubble formation.

To compare materials across different tubing dimensions, we calculated gas uptake rate normalised to 1.0 mm tubing wall thickness

Importance of selecting the right tubing material

It was confirmed that thicker tubing walls could reduce the re-gassing, while also pinpointing that selection of tubing material would significantly change the gas permeability. This study featured several tubing materials including stainless steel, PEEK, ETFE, FEP, PVC (Tygon), PTFE, plus silicone, and it was concluded that ETFE followed by FEP, were the most suitable for typical precision fluidic instrument designs.

The tubing material that best met the criteria of low gas permeability, high flexibility, biocompatibility, and chemical inertness, was ETFE