Other Applications Process Monitoring

HSI is useful for mapping the physicochemical changes in products during a process and can be used, therefore, to monitor the process itself. Unlike in the above 

S Conclusion Some Pitfalls of HSl When Used for Chemical Mapping 

Analysis of the Physical Properties of the Food/Agricultural Items 

In conclusion, thanks to its spatial dimension, HSI can replace setups such as SRS, as they can provide the same type of data, that is, transflectance intensity obtained at various distances from the point source, but at higher resolutions (SRS 

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Other applications of QCM biosensors include real-time monitoring of the agglutination process of human hepatic normal cells (L-02) and hepatic cancer cells (Bel7402) on QCM electrode in the absence and presence of ConA and wheat germ agglutinin.70 This work demonstrated that the QCM measurement technique based on cell agglutination can be used for discriminating hepatic normal cells from hepatic cancer cells. 

Mass spectrometry is also extremely useful as a process monitor. Less sophisticated residual gas analyzers (RGA) operating on the principles of mass spectrometry are available for these purposes and for end point detection. For the etching of Si 128-130), poly-Si 130), silicon nitride 130), and Si02 (729), SiF (m/e=85) has been shown to be effective for end-point detection. In addition, (m/e=14) is useful for nitride 129,130) in leak tight systems, while O (m/e =16), CO (m/e =44) and Si" " (m/e=29) are useful for oxide (757). Because of the general nature of mass spectrometry as a diagnostic tool, it should be applicable to etching studies of metals and other semiconductor materials. 

Internal reflection spectroscopy is widely applied for on-line process control. In this type of application, the chemical reactor is equipped with an internal reflection probe or an IRE. The goal of this type of application is the quantification of reactant and/or product concentrations to provide real-time information about the conversion within the reactor. In comparison with other analytical methods such as gas chromatography, high-pressure liquid chromatography, mass spectrometry, and NMR spectroscopy, ATR spectroscopy is considerably faster and does not require withdrawal of sample, which can be detrimental for monitoring of labile compounds and for some other applications. 

The application of Raman spectroscopy in primary manufacturing was reviewed by Fevotte [25] who put a special emphasis on crystallisation monitoring. It includes tables of typical applications in crystallisation monitoring and other transient processes, respectively. The author concludes that several open questions such as better calibration procedures, dependence on size distribution and sampling techniques need to be addressed before we will see a wider use of Raman spectroscopy in pharmaceutical manufacturing applications. Yu et al. [26] presented a broader review of crystallisation control including in-line Raman for polymorph monitoring. The authors discuss future developments needed for the respective techniques and point out the potential of Raman spectroscopy for in-line polymorph detection. 

Process monitoring, with on-line instruments that operate autonomously for extended periods of time, presents significant challenges and opportunities. The requirements for monitors will vary with the application they support. Where the monitor is set up to support a particular separation process, the analytical objectives may be to determine a single species. The technetium monitor described above, designed to support a technetium removal process, is such an example. On the other hand, some processes may seek to determine multiple actinides in a process stream. These actinides could be a selected group of the transuranic (TRU) elements, or the multiple isotopes of a particular actinide like plutonium. 

Raw data and reports can be stored in the computer s archival memory, but they must be transmitted to the real world to be of use. In the simplest case, they can be displayed on the computer s monitor in the form of chromatographic curves, tables of data, and reports, or they can be sent to the printer for printing. They can also be shared with other computers or with other software applications for further processing and extraction. To move data out of the resident software program, they generally have to be translated into some standard format recognized by other applications. 

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