Infrared spectroscopy, or FTIR, is a type of absorption spectroscopy that uses the infrared portion of the electromagnetic spectrum to examine samples. It is used primarily to measure covalent bonds, and is of great use in organic chemistry.
Infrared spectroscopy can detect the harmonic approximations of a molecule – the combinations of the six different ways covalent bonds can vibrate. In order for a sample to be examined, it must be prepared; liquid samples between two plates of pure salt (which means the sample must be anhydrous), and solid samples crushed and blended with liquid paraffin or potassium bromide so that the spectrometer beam can pass through them.
Once the sample is prepared, a beam of infrared light split into two beams is produced, one beam passing through the sample and the other through a neutral reference. The two resulting beams are passed through a detector and compared.
Infrared spectroscopy is a simple, reliable method for research and industry applications of measurement, quality control, and dynamic measurements. FTIR instruments are small and portable and can even be used in field research.
Infrared spectroscopy, or IR spectroscopy, focuses on the infrared section of the electromagnetic spectrum. Absorption spectroscopy is the most common type of spectroscopy used in this specialty, and is often used to identify compounds and investigate a sample’s composition. Infrared electromagnetism is divided into three portions: near-infrared (14000-4000 cm-1), mid-infrared (4000-400 cm-1), and far-infrared (400-10 cm-1). Far infrared has low energy, and lies near the microwave region. The higher spectrums are useful in studying the structure of substances in a fairly direct manner.
Chemical bonds vibrate at specific frequencies corresponding to their energy levels, and they vibrate in the infrared spectrum. By studying these bonds with infrared spectroscopy, scientists can determine the shape of the outside of the molecules involved, the strength and type of the bonds, and many other things that are hard to determine with other forms of examination. This works with both simple molecules and large complex molecules, provided they have a specific type of dipolarity. In this examination, an infrared light beam passes through the sample, and energy absorbed at each wavelength is examined. The result is plotted and interpreted by the scientist. The bond type it works on is almost always a covalent bond, and that makes it exceptionally valuable in organic chemistry.
Web Resources On Infrared Spectroscopy
The Council for Near-Infrared Spectroscopy
Polymer Analysis, IR Spectroscopy and Raman Scattering
Book Resources On Infrared Spectroscopy
Infrared Spectroscopy: Fundamentals and Applications by Barbara H. Stuart
Infrared Spectroscopy of Biomolecules by Mantsch & Chapman