Looking to measure trace IPA content in water samples.

Only GC I have access to doesn't take samples with water. Different columns not an option.

  • $\begingroup$ The poor man's path: One could roughly estimate the amount of IPA in pure water by adding a photocatalyst (like Vitamin B12 or TiO2...) with appropriate light source, and collect all formed gases by the displacement over the reaction mix. Use say 20 such mixes with known varying amounts of IPA and the data collected to get a precision estimate by statistical analysis. More information from the precise composition of the gas mix may also be of value in the estimation process. See pubs.acs.org/doi/10.1021/jacs.6b06860 as background. $\endgroup$
    – AJKOER
    Commented Sep 5, 2022 at 11:36
  • $\begingroup$ researchgate.net/post/… $\endgroup$
    – ACR
    Commented Sep 5, 2022 at 15:57
  • 1
    $\begingroup$ You can try headspace analysis. $\endgroup$
    – ACR
    Commented Sep 5, 2022 at 15:57
  • $\begingroup$ Good idea unless water vapor is a problem with the GC. If they have access to an FTIR with a multibounce ATR cell such as a circle cell, the C-H stretch bands should be sensitive enough. $\endgroup$
    – jimchmst
    Commented Oct 5, 2022 at 20:24

1 Answer 1


Other than finding any way to get access to a compatible GC (and yes, you can change columns), one might:

Extract the IPA into an organic solvent and then try an IPA shoot. "Salting" the aqueous solution might help, but adding steps for trace analysis adds error, particularly since IPA is volatile.

One might consider speaking to their supervisor about the issue.


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