near-infrared spectroscopy

Near-infrared (NIR) spectroscopy is a technique that uses electromagnetic radiation in the near-infrared region of the spectrum, typically ranging from 700 to 2500 nanometers (nm) or 4,000 to 12,500 wavenumbers (cm^-1). This method analyzes how molecules absorb, scatter, or emit this radiation to reveal information about their molecular structure.123

NIR spectroscopy is particularly useful for identifying functional groups within molecules. When infrared radiation interacts with a molecule, it can cause vibrations, such as stretching and bending of chemical bonds. These vibrations absorb specific wavelengths of infrared light, creating a unique spectral fingerprint for each molecule. Instruments called spectrometers measure these absorption patterns, allowing scientists to deduce the types of bonds and functional groups present. This technique is widely applied in the analysis of organic compounds.23