FAQ - Frequently Asked Questions

Do not use the solvents listed below as the mobile phase when PEEK tubing is used for plumbing. These solvents degrade the strength of the PEEK resin, which could cause the tube to burst and the mobile phase to splash. Use stainless steal tubing.
Tetrahydrofuran (THF), chloroform, hexafluoroisopropanol (HFIP), concentrated sulfuric acid, concentrated nitric acid, dichloroacetic acid, acetone *1), dichloromethane, dimethyl sulfoxide (DMSO).
*1) Briefly using a weak solution of less than 0.5% acetone in water (e.g. in order to check gradient performance) will present no problems.

 

Suppliers of the PEEK resin provide information about chemical resistance of PEEK which states that PEEK is not affected by THF or chloroform. Such information, however, is presented as general guidelines, and it also recommends testing of PEEK parts prior to use under specific conditions for the actual application.
The following are some data from test examples performed by Shimadzu regarding the chemical resistance of PEEK tubing to several types of solvents. Although apparently good results are shown in some combinations of solvent, tubing ID and pressure, this information is merely for reference and should not be taken as guarantee on the chemical resistance of PEEK components.

 

The chemical resistance of PEEK tubing is ranked as A, B, or C for each combination of solvent and tube ID.

This ranking is based on the results of testing done by delivery the solvent through the PEEK tube at the specified pressure for thirty days.
A: There is no cracking, leak, or deformation.
B: There is no cracking or leak, but degrading in mechanical strength such as deformation is observed.
C: There is cracking or leak in the tubing.

Note: Cover PEEK tubing with a protective sleeve when using a high pressure.