Introduction to Fourier-transform infrared spectroscopy

Fourier-Transform Infrared Spectroscopy (FTIR) is a non-destructive technique for analyzing the chemical composition of materials. It measures the intensity and frequency of infrared radiation that is absorbed by molecules in a sample. This technique is widely used in a variety of fields, including chemistry, biology, and material science, among others. It provides information about the functional groups and chemical bonds present in a sample, which can be used to identify compounds and analyze their structure.

Principles and instrumentation of FTIR

The basic principle of FTIR spectroscopy is to measure the absorption of infrared radiation by a sample. The instrument uses an interferometer to generate an interference pattern that is measured by a detector. The sample is exposed to a beam of infrared radiation, which passes through the interferometer and is focused onto the detector. The interference pattern is then converted into a spectrum of infrared radiation, which can be analyzed to determine the chemical composition of the sample.

The instrument used for FTIR spectroscopy consists of a source of infrared radiation, an interferometer, a sample holder, and a detector. The source provides a beam of infrared radiation, which is split into two beams by the interferometer. One beam passes through the sample, while the other beam is used as a reference. The two beams recombine and interfere with each other, creating an interference pattern that is measured by the detector. The resulting spectrum can be analyzed to determine the chemical composition of the sample.

Applications of FTIR in various fields

FTIR spectroscopy is used in a wide range of applications, including chemical analysis, material science, pharmaceuticals, and environmental monitoring, among others. It is used to identify unknown compounds, analyze the structure of polymers, measure the concentration of components in a sample, and monitor chemical reactions in real-time. FTIR spectroscopy can also be used to analyze the quality of food and drugs, and to detect pollutants in the environment.

Advantages and limitations of FTIR spectroscopy

The advantages of FTIR spectroscopy include its sensitivity, accuracy, and non-destructive nature. It provides a wealth of information about the chemical composition of a sample, and can be used to identify compounds that are difficult to detect with other techniques. However, there are also some limitations to this technique. FTIR spectroscopy requires a relatively large sample size and is not suitable for analyzing samples that are highly absorbing or scattering. It is also limited by the spectral resolution of the instrument, which can affect the accuracy of the results.

Example: Real-time monitoring of chemical reactions with FTIR

One example of the use of FTIR spectroscopy is in the real-time monitoring of chemical reactions. This technique allows researchers to observe the progression of a reaction and determine the kinetics of the process. By monitoring the absorption of infrared radiation, researchers can identify the reactants and products in a reaction, and measure changes in the concentration of the components over time. This information can be used to optimize the reaction conditions and improve the yield of the product. FTIR spectroscopy can also be used to study the mechanism of a reaction and identify intermediates and by-products. This technique has many practical applications, including the development of new drugs and industrial processes.