Fourier transform infrared spectroscopy is a molecular spectroscopic method used to determine chemical, preferably organic, structures in substances, substance mixtures or on surfaces. Qualitative and – with increased effort – also quantitative determinations of compounds and structural elements can be performed.

In transmission mode, infrared transmission spectra can be recorded if the respective sample is sufficiently transparent for IR radiation or can be prepared as an adequately thin layer on a transparent substrate.

Due to the existing additional equipment for spectroscopy in attenuated total reflection (ATR) as well as in directed reflection under variable angle of incidence, the FT-IR application possibilities are extended by the analyses of:

• Non-transparent solids
• Thin organic and inorganic layers (down to the nm range) on reflecting substrates
• Non-transparent, even irregularly shaped solids