ISO 19619:2018 specifies an analytical procedure for the determination of free propylene oxide in surfactants which are synthesized from propylene oxide copolymers.

The method is appropriate for the qualitative and quantitative determination of propylene oxide groups in propylene oxide adducts, polyethers and polyglycol esters by headspace gas chromatography (HS-GC) with a flame ionization detector (FID) based on external procedure. Gas chromatography-mass spectrometry (GC-MS) is used for the confirmatory purposes.