Infrared spectrophotometer

Simplified view of an infrared spectrophotometer is shown on the right. Simply, it consists of a:
- source of infrared radiation;
- reference and sample containers;
- an infrared detector;
- recorder.

As shown on the right, the infrared beam is split into two beams and simulatneously passed through the sample and control cells. The two beams are then analysed to produce the infrared spectrum unique to the molecule being analysed.

The control or reference cell is used to discount any absorbance due to the cell material, solvent, water or any laboratory condition that may exist at the time of analysis such as temperature or carbon dioxide levels in the air.