Process Monitoring by Mid‐ and Near‐Infrared Fourier Transform Spectroscopy

Abstract

The sections in this article are Introduction – General Requirements Contrast to Laboratory Instruments Operating Performance Signal‐to‐Noise Ratio Instrument‐to‐Instrument Variability Long‐Term Drift Mean‐Time‐to‐Failure and Mean‐Time‐to‐Repair Calibration Transfer Design Considerations Analyzer Layout Modularity Backward/Forward Compatibility Environmental Influence User Interface Remote Connectivity I / O to Operations Troubleshooting and Diagnostics Power Requirements Reliability Maintenance and Repair Safety‐Regulatory Compliance Electrical Classification American Society of Mechanical Engineers Probe Certification Documentation Training On‐Line Quantitative Procedures FT ‐ IR Transmission Cells Attenuated Total Reflection Sample Systems and Analyzer Shelters Detectors FT ‐ NIR Probes Probe Installations Fibers and Connectors Fibers Connectors Multiplexers Sample Cells Detectors Applications When is the Use of FT ‐ IR or FT ‐ NIR Appropriate for On‐Line Analysis? Implementation Examples of Applications of FT ‐ IR and FT ‐ NIR Impurities in Anhydrous HCl by FT ‐ IR Analysis of Caustic Soda by FT ‐ NIR Attempted Analysis of Aqueous HCl /Aniline Solutions by FT ‐ NIR

A multimodal spectrometer for Raman scattering and near-infrared absorption measurement

“…Vibrational spectroscopy techniques have been adopted for process analyses since 1980s (Tate et al 2002). During the last decade of the 20 th century, NIR spectroscopy has quickly surpassed FT-IR spectroscopy as the method-of-choice for process monitoring (Workman 1999).…”

“…Therefore, the spectrometric system needs to be robust, (Treado and Nelson 2002). Operation of AOTF requires rigid temperature regulation up to 0.001°C to ensure wavelength stability (Tate et al 2002). Therefore, for in-situ, online, and in-line process monitoring, factors such as cost and moderate spectral performance of ETF based spectrometers eluded themselves from further consideration.…”

A Review of Online Real-Time Process Analyses of Melt-State Polymer Using the Near-Infrared Spectroscopy and Chemometrics

“…There are many chemometrics algorithms and methods for the discrimination of samples (1)(2)(3)(4)(5). From those algorithms, a practical and simple method was selected for online discrimination.…”

“…NIR spectroscopy has several important practical advantages for online process analysis: (1) it is suitable for nondestructive and in situ analysis; (2) it permits process analysis using an optical fiber and/or a noncontact probe, thus enabling monitoring in a dangerous environment; and (3) it can be applied to samples of various physical states, shapes, and thickness. Moreover, recent rapid progress in NIR instrumentation, optical fiber techniques, and software have activated the applications of NIR spectroscopy to in-and online process monitoring of chemical and physical properties of the process samples (1)(2)(3)(4)(5)(6)(7)(8).…”

Implementation of Process Analytical Technologies

“…Key operating performance and functional attributes should be addressed in choosing the right technology for the application. 7 Simply stated, the technology should comply with safety and regulatory bodies, give the necessary analytical fi gures of merit for the application, have acceptable LTCO, be reliable and easily maintained, and be user friendly to those using the data generated. Since there are typically several vendors for any given type of process analyzer, a selection process should be completed.…”