While some testing processes are done exclusively for polymers, FTIR testing has a wide range of applications in many different industries. The process will be used in ensuring product quality for regulatory purposes as well as in identifying unknown compounds in a sample.
The most common use of this FTIR or Fourier Transform Infrared testing is for organic compounds as well as for polymers. It uses the principle that infrared radiation passing through a sample is either absorbed or it goes through the sample. The amount of absorption or pass through of the infrared radiation is unique to a given material, which provides a precise identification.
Any given molecule will have a unique way of either absorbing or transmitting the infrared that is different than any other molecule. In some ways this the equivalent of a fingerprint, allowing for precise identification even with very complex types of samples.
The Process
The process of FTIR testing is relatively simple to conceptualize. The sample is placed in the equipment, and an infrared source is used to direct the infrared radiation (IR) to the sample. There is a beam splitter positioned to direct the beam to a detector as well as through the material to a moving mirror as well as a fixed mirror.
This measures the amount of the IR that passes through or is absorbed by the sample. Once the test is completed, the resulting absorption spectrum is then compared to known samples to provide specific information on the tested sample.
It is possible to test solids and liquids as is, as well as to create a film out of pressed samples that can be tested through thin film transmission FTIR processes.
Through the use of FTIR testing, it is possible to determine the exact components in an unknown sample. It is also a very precise way to identify if any contaminants are present in a known material.
