Gas Chromatography - Tandem Techniques - The Characteristics of Infrared Absorption > IR Spectroscopy Instrumentation > The Simple Grating Infrared Spectrometer > Page 28

 

The interpretation of spectra requires considerable skill and, unless the analyst is also an experienced spectroscopist, verification should be sought to confirm any conclusions that are drawn from the spectra of an unknown substance.

 

IR Spectroscopy Instrumentation

 

There are two basic types of IR spectrometer in use today, the simple grating dispersion IR spectrometer and the Fourier transform IR spectrometer (FTIR). The former has now, been almost completely replaced by the latter which is much faster. In a few years time, it is probable that only the FTIR instrument will be in use with combined systems. Nevertheless, as there are still some grating instruments in use at this time, both systems will be described. The two spectrometers are quite different in design and function.

 

The Simple Grating Infrared Spectrometer

 

A diagram of the grating IR spectrometer is shown in figure 18.

 

 

 

 

Figure 18. The Simple Grating IR Spectrometer