Advantages of FT-IR Spectrometers

• As the absorption at all wavelengths is recorded at the same time, this saves lot       of experiment time. This is called the multiplex or Fellgett advantage. This       leads to a spectrum with a better signal to noise (S/N) ratio in the same time as       compared to a dispersive instrument.
• These are much faster and a given spectrum can be taken in less than a second.
• This provides for taking multiple scans for low concentration samples and then

      averaging them.

• FT-IR spectrometers give better frequency resolution and reproducibility.
• As there are no narrow slits in an FT-IR spectrometer, the energy output is much greater than in a dispersive instrument. This is referred to as the Jacquinot dvantage. This also leads to a higher signal to noise ratio (S/N ratio) than the       dispersive infrared spectrometers.
• In some FT-IR spectrometers a helium neon laser is used as an internal  reference. This provides an automatic calibration with an accuracy of better than

cm–1 and eliminates the need for external calibrations. This internal laser reference is called Connes advantage.

• These can be easily adapted for remote use. For example, the beam may be diverted to pass through an external cell and detector, as in GC- FT-IR.
• Due to its simple mechanical design with only one moving part (the moving mirror in interferometer), there is less wearing out of the components and hence

      better reliability of the spectrometer.

• Even though the spectra of many samples can be easily run on either FT-IR or

dispersive instruments; the FT-IR spectrometers are the preferred choice for  samples because of higher sensitivity.