Headspace (HS)

Solids and liquids exist in equilibrium with a vapor phase at the solid/air, or liquid/air interface.  The position of the equilibrium is determined by several variables (temperature, pressure, matrix modifier, phase ratio, etc.).  If the material is in an enclosed container, the remaining void not occupied by the material is termed the "headspace" and will reach an equilibrium vapour concentration that is representative of and proportional to the source material. It is then possible to sample and analyse this headspace in place of the parent material. This technique is most appropriate for volatile compounds that produce an appreciable vapor pressure.

Headspace techniques

• Dynamic HS (DHS)
• Static HS (SHS)