Infrared Spectroscopy Types and Their Applications for Chemical Reaction Monitoring

The fast and cost-effective technique called Infrared (IR) spectroscopy is well recognized for the characterization of a wide range of materials. Infrared spectroscopy can provide conclusive information about samples, and it is ideally suited to both qualitative analysis of materials and quantification of components.

The IR region of the spectrum is generally split into three different sub-regions:

  • Far-IR: 400-30 cm⁻¹

The Far-IR region is primarily used for meaning inorganic molecules.

  • Mid-IR: 4000-400 cm⁻¹

The Mid-IR region consists of fundamental absorption bands and provides a molecular fingerprint. This is beneficial for simple structural investigation and raw material ingredient or additive identification by library comparison.

  • Near-IR: 14000-4000 cm⁻¹

The Near-IR region is particularly useful for food applications, including moisture, fat, and protein content determination. The Near-IR region arises from overtones and combination band of the fundamental bands in the Mid-IR region.

Over the past twenty years, the use of the Near-IR region of the spectrum for a wide variety of the analytical procedures has grown precipitously. While NIR spectroscopy has found many broad applications in individual process management, NIR advocates have sometimes tended to become overzealous in applying NIR to all industrial analysis. However, it should be noted, other procedures such as Raman and Mid-IR spectroscopy could provide more useful analytical data. For example, calibration in the Mid-IR region is much more generic than that in the Near-IR region and thus is more readily transferable from instrument to instrument.

Mid-infrared (MIR) spectroscopy provides benefits in chemical reaction monitoring. In other words, such spectroscopy offers simultaneous monitoring of many chemical species, and it can look more comfortably at functional groups for the liquid process. MIR allows the observation of particular compounds monitoring whereas near-infrared (NIR) spectroscopy allows only the observation of general reaction monitoring. The more detailed information about chemical mechanisms can be obtained from the combination of both datasets.

Only a clean observation window can provide reliable analysis at any time during chemical and biological processes.

Optical methods can be used only when some procedures are carried out at any time and in a reliable manner such as:

  • Cleanliness check of the observation window
  • Cleaning of the observation window
  • Zero baseline at any time
  • Active control over the complete analyzer
  • Complete cleaning of all parts which have contact with a product (surfaces, seals, etc.) following the guidelines of GMP, Hygiene, etc.

An automated fiber optic analyzer system can be incorporated into the reaction by employing approved fittings and flanges. The modern semi or fully automated analyzer systems are used in sensitive and high safety processes. They are modified in such a way that they enable optimal usage and cleaning of fiber optic immersion probes.

Optromix cleanable fiber probes with process interfaces are designed to be used for reaction monitoring with no artifacts caused by optic contamination as they can be retracted, cleaned, and calibrated during a chemical process. Senso Gate-FOS and Ceramat-FOS made by KNICK are the process interfaces that have approved fittings and flanges for the probes to secure their semi or fully automated use in the complete process systems.

If you would like to buy Optromix cleanable fiber probes with process interfaces, please contact us at

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