FTIR Spectroscopy is a technique based on the determination of the interaction between an IR radiation and a sample that can be solid, liquid or gaseous. It measures the frequencies at which the sample absorbs, and also the intensities of these absorptions. The frequencies are helpful for the identification of the sample's chemical make-up due to the fact that chemical functional groups are responsible for the absorption of radiation at different frequencies. The concentration of component can be determined based on the intensity of the absorption. The spectrum is a two-dimensional plot in which the axes are represented by intensity and frequency of sample absorption.
PRINCIPLES OF IR SPECTROSCOPY
The different regions of the electromagnetic spectrum will be used in this section to learn about the structure and reactions of organic molecules. For each spectroscopic method, it is helpful to understand how much energy corresponds to each wavelength and how this relates to the physical process after absorption of radiation. Organic molecules can absorb IR radiation between 4000 cm-1 and 400 cm-1 which corresponds to an absorption of energy between 11 kcal/mole and 1 kcal/mole. This amount of energy initiates transitions between vibrational states of bonds contained within the molecule.
APPLICATIONS OF FT-IR SPECTROSCOPY
Applications to all fields have been developed in our laboratory they include subjects such as:
- Food analysis: additives, preservatives, colorants.
- Environmental analysis: water, atmospheric particles, gases.
- Conservation and restauration of heritage: paintings, sculptures, ceramics, fossils, ivories.
- Forensic science: paints, textiles, cosmetics.
- Semiconductor analysis.
- Physiological samples: malignant cells, bones, hairs.
- Multilayer compounds: polymers, paintings, films.
- Geological samples: inclusions in stones.