Infrared spectroscopy (IR) is ideal for the rapid classification of an organic contamination. Compared to the SEM/EDX method, this method does not determine the elemental composition of the sample but detects the vibration of the atoms in a molecule. For example, polyethylene ([CH₂]_n) and polystyrene ([C₈H₈]_n) each consist only of the elements carbon and hydrogen. The determination of the elemental composition does not provide any information about the material. Due to the different structure of the polymers, however, they can be distinguished very precisely by means of IR spectroscopy.

By comparison with spectral databases, it is possible to quickly assign pure compounds to the corresponding material classes. Mixtures of substances, as they are often found in commercially available formulations, can also be detected with a certain accuracy. Customer-specific reference samples can furthermore be used for comparison. This enables the creation of tailor-made databases. In the event of damage, the origin of the problem can thus be quickly identified.

In combination with further analyses such as GC/MS, impurities can be determined and quantified quickly and reliably.