What is a infrared spectrometer?

Question

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!

Answer 1

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)

Answer 2

The energy in the chemical bonds of organic molecules matches the wavelenghts we know as infrared (190 to 400 nanometers). Each kind of bond does absorb light at an specific energy ( C-C, C-O) so this kind of spectrometer allows the analyst to know the structural parts of a molecule. it also works extremely well for quantitative analysis. IR spectrometry together with mass spectrometry and RMN (used together) are the unique techniques that allow a new molecule or organic compound to be characterized. Before IR spectrometry every new compound was just a guess, confirmed by indirect means.

Answer 3

Any kind of spectrophotometer shines light of some range of wavelengths through a sample and measures the amount of light of different wavelengths that are absorbed by the compound(s) in the sample. An IR spectrophometer uses and measures the absorption of infrared light. It is used by organic chemists to help identify or characterize a compound. There isn't really any other kind of instrument that gives you the same information.

I'm not really sure of specific things that were first found out using infrared spectrophotometers. Perhaps a google search might help you find out something specific...