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Suppose we have some fermented (optionally also distilled) fruit/fruit juice. The sample therefore contains water, sugars, ethanol etc. Which analysis method is the simplest to find out whether the toxic methanol is also present?

Martin - マーチン
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user5320
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2 Answers2

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Methanol, formed by degradation of pectines from the skin of fruits, as well as higher alcohols is volatile and does not show significant absorption in the UV.

Consequently, gas chromatography is the method of choice to determine these components in the fermentation mix.

Klaus-Dieter Warzecha
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Maybe try NMR?

But if the amount of the methanol is too small, you won't see so beautiful signal:

enter image description here

XuMuK
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  • Nice answer! What program generates such a nice NMR-spectrum? – andselisk Aug 07 '17 at 01:34
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    @andselisk I got this image from this site: https://www2.chemistry.msu.edu/faculty/reusch/virttxtjml/spectrpy/nmr/nmr2.htm to simulate NMR there are a lot of web-pages: https://web.chemdoodle.com/demos/simulate-nmr-and-ms/ it can predict OH (most of them can't) for example: www.nmrdb.org/new_predictor/ As software I prefer Mnova http://mestrelab.com/ or Chemdraw http://www.cambridgesoft.com/software/overview.aspx - both are not free. – XuMuK Aug 07 '17 at 11:46
  • I'm aware of both Mnova and Chemdraw, but to my knowledge none of them can produce this pixel-perfect plot. But thank you anyway! – andselisk Aug 07 '17 at 11:50
  • @andselisk Ususally, I prefer EXPERIMENTAL data bases, something like: http://sdbs.db.aist.go.jp/sdbs/cgi-bin/cre_index.cgi for small compound it is much better than prediction. Here is small comparison http://imgur.com/a/EIjLW – XuMuK Aug 08 '17 at 08:38