ATR-FTIR analysis

What is ATR-FTIR used for?

ATR-FTIR is used in various research areas and industries to obtain information on the chemical components of a sample. Examples of ATR-FTIR applications include material identification in the plastics industry, pharmaceutical industry quality control, and biological research. The method is also used for chemical characterization in industries including consumer goods, food, fuel, and biorefinery.

How does attenuated total reflection work?

The ATR-FTIR apparatus consists of an infrared light source, a detector, and a crystal with a high refractive index, such as diamond, germanium, or zinc selenide. The sample is placed on the crystal and infrared light is directed at it. The light passes through the crystal and partially penetrates into the sample, where some of it is absorbed in an area called the evanescent field. 

The rest of the light is reflected to the detector, where it is detected, allowing an FTIR-ATR spectrum to be produced. When compared with a library of known spectra, the obtained spectrum can help identify the sample's chemical composition.

The advantages of using ATR in FTIR sampling.

ATR allows for a wide variety of sample types, including liquids, solids, powders, and solutions, to be tested whilst creating consistent, reproducible results. It generally requires very little sample preparation compared with other forms of FTIR and only requires a small amount of sample to produce high-quality results. In most cases, the sample can be recovered after analysis, and cleaning the equipment is also straightforward.

Single-reflection vs. multi-reflection ATR sensors

In most ATR-FTIR spectrometers, the infrared light is reflected from the surface boundary a single time before being detected. Multi-reflection ATR sensors have a larger crystal which allows the light to reflect multiple times before being detected. The benefit of this is that it can increase the sensitivity for particularly weak absorbances, making it ideal for harder-to-detect chemical groups, and for testing low-concentration solutions.

Need an analysis?

Measurlabs offers a wide range of chemical analysis services with methods including FTIR-ATR, HPLC-MS, NMR spectroscopy, and many others. You can request a quote for your material using the form below. One of our testing experts will take ownership of your project and get back to you within one business day.