Fourier-Transform Infrared Spectroscopy (FTIR)

 Fourier-Transform Infrared Spectroscopy (FTIR)

Fourier-Transform Infrared Spectroscopy (FTIR) is a powerful analytical technique used to study the interaction of infrared (IR) radiation with matter. It is widely used in various fields, including chemistry, biology, materials science, and environmental science, to analyze and identify chemical compounds, determine molecular structures, and study various molecular processes.

  Principle of FTIR Spectroscopy:

• FTIR spectroscopy is based on the principle that molecules absorb specific frequencies of infrared radiation, causing vibrational and rotational transitions. These absorption frequencies are characteristic of the chemical bonds and functional groups present in a molecule.
• A typical FTIR spectrometer consists of a broadband IR light source (often a Michelson interferometer), a sample compartment, and a detector.
1. Sample Preparation:
• To perform an FTIR analysis, a sample is prepared as a thin film, a solid pellet, a liquid solution, or a gas in a suitable cell or holder, depending on the nature of the sample.
2. Measurement Process:
• In FTIR spectroscopy, the IR radiation is passed through the sample. The sample absorbs specific wavelengths of the IR radiation, and the transmitted light is measured.
• The Michelson interferometer is used to modulate the incoming IR radiation by varying the path length difference between two arms of the interferometer.
• The resulting interferogram is then subjected to a mathematical transformation called Fourier transformation, which converts the data from the time domain into the frequency domain, generating an IR spectrum.
3. Interpretation of IR Spectra:
• The IR spectrum produced consists of peaks at specific wavenumbers (reciprocal of wavelength) corresponding to the absorbed frequencies.
• Analysts can interpret these peaks to identify functional groups, chemical bonds, and structural features of the molecules in the sample.
4. Applications of FTIR Spectroscopy:
• Chemical Analysis: FTIR is widely used in chemical analysis to identify and quantify components in mixtures. It is valuable for quality control and forensic analysis.
• Pharmaceuticals: It is used to verify the identity and purity of pharmaceutical compounds.
• Polymers: FTIR helps in the characterization of polymers, including assessing their chemical composition, structure, and stability.
• Environmental Science: It is used for analyzing air pollutants, detecting hazardous substances in soil and water, and studying atmospheric chemistry.
• Biology: FTIR can be used to study biomolecules like proteins, lipids, and nucleic acids.
• Materials Science: It is crucial for characterizing materials such as ceramics, semiconductors, and coatings.