First things first. What is FTIR imaging?
In an FTIR image (often called chemical image), each pixel is composed of an entire IR spectrum. These images allow a very detailed and spatially resolved chemical analysis based on a sample’s spectroscopic properties. By interpreting this often massive amount of data, sample properties like chemical structure or composition can be visualized by rendering false color images.
Where is FTIR imaging used?
This is of great value for many industries, and is used in research and development, as well as QC and root cause analysis. Real-life examples are the assessment of polymer coating uniformity, the distribution of APIs in pharmaceuticals or the investigation of biomarkers in biological tissues.
From automotive industries to pharmaceutical formulation development to life-science and microplastic particle analysis. The applicability of FTIR imaging is almost endless and our experts at Bruker are always ready to claim unchartered land and develop exciting, new solutions.
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Figure 1: Chemical FTIR Image of a pharmaceutical tablet.
A specific color was assigned to each component.
How are FTIR images created?
Usually, single point, line array and focal plane array (FPA) measurements are the methods of choice for generating such images. Of course, the performance varies across these different approaches.
In single-point imaging, each measurement point of a defined grid is approached and measured. This means a high investment of time, whereas highly automatic microscopes reduce this effort.
In line array detectors, individual detector elements are arranged in series (e.g. 1x8) and record a "line" of spectra that are "stitched" together after measurement, to form a chemical image.
About the dominance of FPA detectors.
Focal-plane array detectors are composed of a set of infrared light-sensitive pixels in the focal plane of a lens - just like a digital camera. This way it is possible to image the desired field of view without the need for time-consuming scanning procedures.
The data is recorded in perfect alignment with the visual image, regardless of the sample structure. So naturally, FPA detectors easily outperform classical consecutive single-point or line-array measurements in terms of speed and precision.
Bruker recently expanded and bolstered its FPA imaging microscopy line-up and introduced the LUMOS II FTIR microscope. It is equipped with a 32x32 pixel line array detector and collects an impressive number of 1024 spectra per scan.
And this brings us back to our first question: why should you (re)consider FTIR imaging? Because the LUMOS II is a game changer, and here is the reason:
>900 spectra per second, at 5 µm resolution.
Sounds great? Looks impressive! We recorded a short video showing the real-time analysis of a microtome tissue cut. Measurements where done with the LUMOS II and the latest version of our OPUS spectroscopy software. The image was recorded with over 900 spectra per second, at 5 µm pixel resolution and over an area of 1 x 1 mm².
FTIR Imaging by FPA and LUMOS II
Further information
If you want more information, you can visit our website or contact us directly and talk to application scientists.