The vials are used to heat the sample until the concentration of the liquid and gas phases are in equilibrium. A sample is then taken from the gas phase (headspace) for analysis. European 20mm Crimp and 18mm Screw Thread Headspace Vials with Rounded Bottoms – use in Aijiren, Carlo Erba, CTC PAL, Fisons, Perkin Elmer, Tekmar and Varian (6)