FTIR Spectroscopy

Fourier-transform infrared spectroscopy identifies the functional groups present within a molecule by their characteristic vibrational absorption...

Fourier-transform infrared spectroscopy identifies the functional groups present within a molecule by their characteristic vibrational absorption frequencies across the 4000–400 cm⁻¹ range, with each distinct functional group — hydroxyl, carbonyl, amine, aromatic, and others — producing absorption in a well-established, diagnostic frequency region. FTIR is typically performed as one of the earliest confirmatory analyses following a synthetic reaction, since the appearance or disappearance of a characteristic functional-group absorption (for example, the emergence of a carbonyl stretch near 1700–1750 cm⁻¹ following an oxidation reaction) provides rapid, qualitative confirmation that the intended transformation has occurred, ahead of the more detailed and time-consuming NMR and mass spectrometric analysis that follows.