FT–IR spectroscopy

The most valuable application of FT-IR microscopy is in the chemical mapping of a sample of varying composition. For example, it can be used to study food materials, such as the chemical composition of wheat grains, and different layers in laminated plastic packaging.

Contact us

Before you Send please insert the same letters and numbers you see in this image captcha_image into this box: (this helps us fight spam)

When you click on the Send button you will be deemed to have accepted our terms and conditions


FT–IR Spectroscopy is an extremely versatile analytical tool which can be used to analyse a wide range of organic materials, and some inorganics as well.

A particularly important application is the identification of foreign bodies reported from food, such as this fragment of plastic. The plastic is placed over the diamond window of the device and pressed down to achieve very close contact with the diamond: this close contact is essential for the system to work. Powders can be analysed by crushing them against the diamond crystal. Liquids are analysed by placing a small drop of the test liquid on the diamond crystal.

Results are displayed on the PC monitor. The computer then searches its library of known spectra of different materials to make an identification.

When pouches leak or lidding film fails to seal properly to a food tray, it is important to identify which layer of the material has failed. FT-IR microscopy can identify each of the plastic layers in order to trace the source of the problem.

A Focal Plane Array Detector [cooled by liquid nitrogen], enables us to analyse the different layers simultaneously and create a chemical map of the cross–section. The sample is first focussed under the beam, when the different layers can be seen. A germanium crystal is then placed in front of the microscope lens and the sample pressed gently against it.

The microscope then generates a chemical map of the cross–section which is seen here as a 3–D image, the different colours representing different layers of the plastic laminate. The infra-red spectrum of each layer can then be compared with library spectra to make an identification.

More on Analysis and testing

Dog eating out of pet food bowl

Pet foods and the unknown risk to human health

Over the years, the pet food industry has suffered several foods scares resulting in adverse health effects to those owning pets and financial impacts. In th...

Meat balls

Meat testing – ensuring quality and safety

Testing of meat and meat products can be used to assess quality, safety, performance and compliance with prescribed standards, both external and internal, an...

Scientist looking into microscope

Packaging under the microscope

This webinar explains how microscopy techniques can be used to assess the plastics and metals commonly used in food and drink packaging. ...

Pizza in takeaway box

Bans of perfluoroalkyl substances (PFAS) in food packaging gain traction: Get ready with PFAS testing

Governments around the world are currently trying to remove PFAS from the food supply, as well as the environment. A patchwork of new legislations in recent ...

supermarket shelves

List of food recalls for ethylene oxide grows

European countries and the UK are facing more ethylene oxide related recalls after the substance was detected in more food additives used in a large range of...

Allergen labelling for foods prepacked for direct sale (PPDS)

Allergen labelling for foods prepacked for direct sale (PPDS)

From 1 October 2021 in England, Wales, Scotland and Northern Ireland, any food that is prepacked for direct sale (PPDS) must have appropriate labelling.

Contact an expert