Gas Chromatography/Infrared Spectroscopy
Published Online: 15 SEP 2006
Copyright © 2000 John Wiley & Sons, Ltd. All rights reserved.
Encyclopedia of Analytical Chemistry
How to Cite
Le Quéré, J.-L. 2006. Gas Chromatography/Infrared Spectroscopy. Encyclopedia of Analytical Chemistry. .
- Published Online: 15 SEP 2006
Gas chromatography/infrared (GC/IR) spectroscopy coupling combines the separation power of high-resolution gas chromatography (HRGC) to the highly specific identification technique, infrared (IR) spectroscopy, based on the absorption of IR radiation by the molecules. Relying on different molecular properties, IR is an excellent complement to mass spectrometry (MS) in structural analyses. For volatile compounds, the coupling of gas chromatography/mass spectrometry (GC/MS) has been the universal basic technique for a long time. The advantages of Fourier transform infrared spectrometry (FTIRS) allowed the coupling of gas chromatography (GC) to an FTIR (Fourier transform infrared) spectrometer, ending with a powerful tool, gas chromatography/Fourier transform infrared spectrometry (GC/FTIRS). The first device developed to interface a gas chromatograph to an FTIR spectrometer was a flow-through gas cell, known as the light pipe (LP), delivering vapor-phase IR spectra of eluting solutes. Two other cryogenic devices which allowed mobile-phase elimination by trapping the compounds eluting from the GC at sub-ambient temperature have been developed: the matrix isolation (MI) interface operating at 11 K and the direct deposition (DD) window operating at 77 K. Each of these three types of interface has advantages and drawbacks that are discussed in terms of sensitivity and specificity. Some selected applications in selected domains of analytical chemistry, i.e. environment, flavor and fragrances, pheromones and fatty acids, are presented and discussed again in terms of sensitivity and specificity according to the interface type used. Finally some concluding remarks on technique developments for GC/FTIRS and related techniques combining chromatography with IR spectroscopy are given.