I know you can use GC-MS for the analysis of gaseous molecules, but would you be able to instead use an infrared spectroscopy method to analyse gaseous molecules, or does it need to be mass spectroscopy?

  • $\begingroup$ You could use IR, but IR is more limited in specificity. With IR n-pentane looks very similar to n-hexane for example. IR would be cheaper and easier to maintain, so there are pluses. $\endgroup$
    – MaxW
    Mar 16, 2016 at 23:26
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    $\begingroup$ @MaxW Using IR to distinguish n-pentane and n-hexane would indeed be a bad idea. Perfect for distinguishing isomers of ethyltoluene though. IR as a technique has may advantages over MS such as determining aromatic substitution, ring isomers, cis/trans isomers, ring junctions etc. Perfect for fatty acid analysis where only subtle differences in double bond position exist. Like all methods, the key is to pick the right tool for the job. $\endgroup$
    – long
    Mar 16, 2016 at 23:48

1 Answer 1


GC-MS is just one common method of what is known as 'hyphenated' analysis. GC-IR instruments do exist (see examples), although usually involve some pretty specialised cells to allow for gas flow through the sensor. Hyphenated instruments are limited pretty well by your imagination (and budget) only. LC-NMR-MS is a great example of extended hyphenation, and is a powerful emerging tool for automated analysis of complex sample mixtures.

  • $\begingroup$ Wow, Bruker does more than NMR? $\endgroup$ Mar 17, 2016 at 0:28

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