Infrared (IR) spectroscopy is a vibrational spectroscopy based on photon-matter interaction. The energy absorption by a molecule induces in particular vibrations (stretchings noted ν and bendings noted δ).

It allows for the identification of certain chemical functions of a compound. It is possible to perform quantitative analysis in infrared and thus to quantify a compound in a mixture. With few sample preparation steps, this technique is well suited for the analysis of solid, liquid or gaseous samples.