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Infrared Spectroscopy in Process Analysis

Process Instrumental Methods

  1. John P. Coates1,
  2. Paul H. Shelley2

Published Online: 15 SEP 2006

DOI: 10.1002/9780470027318.a2108

Encyclopedia of Analytical Chemistry

Encyclopedia of Analytical Chemistry

How to Cite

Coates, J. P. and Shelley, P. H. 2006. Infrared Spectroscopy in Process Analysis. Encyclopedia of Analytical Chemistry. .

Author Information

  1. 1

    Coates Consulting, Newtown, USA

  2. 2

    Boeing Commercial Airplane Group, Seattle, USA

Publication History

  1. Published Online: 15 SEP 2006


Infrared (IR) instruments have been in use as important measurement and analysis tools for process monitoring and production control for more than half a century. They range in complexity from the simplest filter-based photometers to opto-mechanically complicated devices, such as Fourier transform infrared (FTIR) instruments. Simple nondispersive infrared (NDIR) instruments are in common use for systems where one to a few main analytes are involved. For more complex measurement situations it is necessary to record more spectral information, and often full-spectral analyzers are used. Of the main analytical instrument techniques, IR analysis is the most versatile, where all physical forms of a sample may be considered – gas, liquids, solids and mixed phase materials. A wide range of sample handling options exists, and many of these may be adapted to either near-line/at-line production control or on-line process monitoring applications. Instrumentation used within a manufacturing environment usually requires special packaging to protect the instrument from the environment, and to protect the operating environment from the instrument. This places special constraints on the way that an instrument is designed and the way that it performs. Often, it is necessary to utilize special technologies, normally not required for laboratory instruments, to meet the performance objectives. For most practical installations within a production environment it is a normal requirement for the final instrument to comply with local manufacturing and electrical safety codes. The range of applications of IR spectroscopy is extremely broad and the technique can play an important role in virtually all industries for manufacturing quality and production control, and for environmental monitoring.