The Process

• A sample is placed into an FTIR spectrometer. The light source will pass different wavelengths of light through the sample. On the other side of the sample is a detector which detects the light that is transmitted through the sample.
  
  

Algorithm

• Fourier algorithms are used to transform the absorbance and transmittance information into a spectrum. These algorithms are complicated and a computer program is used for the calculations.
  
  

Spectrum

• Each peak on the infrared spectrum, will correspond to a chemical bond. By comparing the percent transmittance for each wavelength and comparing them with known chemical transmittance it is possible to determine the structure of unknown compounds.
  
  

Background

• Normally a background spectrum is collected along with the sample spectrum. This will remove instrument characteristics from the sample spectrum. Think of it as zeroing the machine before running a sample.