What Are the Applications of IR Spectroscopy?

Infrared light has a lower frequency and longer wavelength than visible light, making it invisible to the human eye. Infrared (IR) Spectroscopy uses this range of the electromagnetic radiation spectrum to gain insight into the chemical composition of matter. Wavelengths generally range from between 700 nanometres (nm) and 1 millimetre (mm), with absorption, emission and reflection patterns used for both qualitative and quantitative analysis.

The technique is used across a wide range of industries and is suitable for all sample types, including solids, liquids and gases. Read on to find out more about the applications of IR Spectroscopy, including common uses and some more unconventional applications.

• Measuring environmental pollutants

High sensitivity and selectivity make IR Spectroscopy for analysing complex mixtures. The technique has become a mainstay in for environmental scientists, who use it to detect industrial pollutants in the atmosphere. From monitoring air quality in major cities such as London and Tokyo to tracking methane concentrations in the Arctic, IR Spectroscopy offers a wide range of applications for environmental science.

• Preserving contemporary artworks

Preserving contemporary artworks has recently emerged as a novel use for IR Spectroscopy. In a study published in the journal Scientific Reports, the authors introduce IR Spectroscopy as a technique to detect and quantify plasticisers such as phthalates, adipates, terephthalates and citrates in PVC objects of historic value.

“Because of its versatility PVC has also been used as a material for artworks and represents a significant part of modern and contemporary collections,” reads the report. “For the first time, a large and diverse collection of more than 100 PVC objects in different degradation stages and of diverse chemical compositions was analysed by chromatographic and spectroscopic techniques to create a dataset used to construct classification and regression models. Accounting for this variety makes the model more robust and reliable for the analysis of objects in museum collections.”

• The development of medical libraries

Variations of IR Spectroscopy are making waves in the medical sector, with a team of researchers from the Department of Pathology & Laboratory Medicine at Aga Khan University in Pakistan recently using Fourier Transform Infra-Red (FTIR) Spectroscopy to develop a patient gallstone library.

“The library developed displayed good consistency and can be used for detection of gallstone composition in Pakistan and replace the traditional labour and time-intensive chemical method of gallstone analysis,” reads the conclusion of the report published in the medical journal, BMC Gastroenterology.

Expanding the spectrum

While analysing patterns in the infrared region of the electromagnetic radiation spectrum is useful for some applications, scientists are also concerned with the Near-Infrared (NIR) and UV-Visible (UV/VIS) ranges. Find out more in ‘What Are the Different Types of Spectroscopy?’