The automobile industry has been practicing Process Analytical Technology (PAT) for many years. PAT is a process validation and control system for process quality control and cost efficiency.
In the chemical industry, the processes are not taking place in large open production lines but in difficult to access processing tanks, often in aggressive media and under very high temperature and pressure conditions in some cases.
Hence, it is not always possible to use conventional testing methods, tools, or operating procedures for process control.
FT-NIR Spectroscopy
In the chemical industry, process control needs to take place at a molecular level. It is therefore essential to use advanced PAT techniques such as FT-NIR spectroscopy, which facilitates improved production efficiency with a more consistent quality.
FT-NIR spectroscopy is perfectly suited to the direct monitoring of chemical reactions, in addition to ensuring the quality of intermediate and final product in chemical manufacturing facilities.
Modern analytical tools can be employed in all stages of production, thus enabling transmission of data on single processes over extended distances directly from process tanks or bypass through quartz fiber optics. This, in turn, allows the data to be analyzed at a distance, away from the extreme ambient conditions of the process, such as elevated temperatures and pressures.
Immersion Probes or Measuring Cells
Immersion probes or measuring cells that are designed to perform under hostile conditions are used to constantly assess the data in real time. The selection of the materials for the immersion probes (Figure 1) is based on the chemical composition of the process.
These materials include robust Hastelloy alloys, different stainless steel grades, or even extremely resistant tantalum.
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Figure 1. Immersion Probes
The optical materials employed in immersion probes and measuring cells can also be custom-made to match the process. Sapphire and quartz do extremely well, thanks to their ultra-high degree of precision.
Sapphire in particular is often chosen by users, due to its chemical resistance. The immersion probe or measuring cell required can be chosen through modular design principle and custom-made to the individual process conditions existing on site.
Application Areas
The following are the frequently used application areas for the combination of FT-NIR spectroscopy, immersion probes and measuring cells:
- Understanding of reactions – Real-time analytical monitoring of new processes is possible during the development phase
- Process monitoring – Quantitative determination of the material composition of intermediates and final products is possible
- Quality assurance – Ensuring purity of intermediates and final products, for instance, water content etc.
- Goods received inspections – Allows Identification of delivered goods or products by their NIR spectra (fingerprint) to prevent faulty material mix-ups or filling of storage tanks
Besides chemical production, these application areas can also be found in other industries, including the food industry, the pharmaceutical industry, and the plastics and polymer industry.
Application in the Pharmaceutical Industry
In the pharmaceutical industry, a very frequent application is the identification of cloud point in the production of active substances for pharmaceuticals. These substances need to undergo different tests to reach the next phase of approval.
A key test is the identification of the cloud point corresponding to temperature, for which traditional turbidity measurements are normally used. Immediately reaching a certain temperature, the active substance starts to crystallize and the turbidity increases. This is a consistent process wherein the turbidity increases steadily.
Determining the temperature at which the cloud point is achieved is a difficult task. The combination of an immersion probe and a spectrophotometer can determine the temperature of the turbidity point accurately and conveniently.
There is a significant change in the absorption spectrum of the solution at the onset of crystallization. This abrupt and clearly visible change in the optical spectrum facilitates accurate monitoring of this process.
About Hellma Analytics Optical Immersion Probes
Hellma Analytics develops and distributes cuvettes and optical components for laboratory equipment in modern analysis technology.
Hellma Analytics specialise in:
- Chemical and pharmaceuticals
- biotechnology
- food industry
- health care
- environment
This information has been sourced, reviewed and adapted from materials provided by Hellma Analytics.
For more information on this source, please visit Hellma Analytics.