text: what is a infrared spectrometer? i really need to know the purpose of a infrared spectrometer. are they any other methods of getting similiar results. did this open any doors as to finding something else? please help! also see the web portals given in the references.  a beam of infra-red light is produced and split into two separate beams. one is passed through the sample, the other passed through a reference which is often the substance the sample is dissolved in. the beams are both reflected back towards a detector, however first they pass through a splitter which quickly alternates which of the two beams enters the detector. the two signals are then compared and a printout is obtained.  a reference is used for two reasons:  this prevents fluctuations in the output of the source affecting the data  this allows the effects of the solvent to be cancelled out (the reference is usually a pure form of the solvent the sample is in)