The design of the attachment for headspace analysis of liquids for the FT 801 Fourier transform infrared spectrometer is described in detail. The advantages of headspace analysis of liquids are emphasized, which make it possible to identify impurities in a solution with a concentration of less than 1%. Sharp, narrow, well-resolved lines of individual components of a vapor mixture make it possible to easily determine its individual components, which is impossible in liquid cells due to the broadening of spectral lines due to strong intermolecular interactions. Additional capabilities and the purpose of the new attachment to spectrometers that have long proven themselves to be the best are noted.