Science paper on SHU testing

http://www.chromatographyonline.com/simple-and-fast-quantification-capsaicinoids-hot-sauces-using-monolithic-silica-capillaries-and-lc-m
 
Neato! Always wonder how they go about testing with HPLC. Hope this is in the correct forum.
 
(all materials belong to their respective authors/etc)

I got interested in how they separated the capsaicin from the pepper sauce.
 
I had to look up the Soxhlet extraction process.
 
https://en.wikipedia.org/wiki/Soxhlet_extractor
 
It got me thinking...  I bet the excess water in the pepper sauce would play hell on the extraction.  The water should accumulate in the collection pot, which should affect the solubility.
 
I'd have been tempted to use something aromatic like benzene, toluene, or xylene.  You can modify the condenser to separate out the water, which should make the extraction more efficient.
 
I can see why the methanol was so much more efficient than the ethanol.  Anytime you're boiling ethanol/water, you're going to have a lot of water boiling up with the ethanol, which will probably make the extraction go more slowly.  If you're boiling methanol/water, the vapor stream is more concentrated with methanol, so the extraction pot is seeing less water.
 
It worries me that their extraction method yields a supernatant solution.  This could be due to the water accumulation in the extract knocking the capsaicin out of solution, which could of course totally mess up the results.
 
It makes me wonder if benzene combined with a modified condenser (to separate out the water) would yield a regular solution, instead of having solids (which could be some of your capsaicin) that need to be filtered.

[SIZE=10.5pt]I'm a bit surprised they didn't do a quick drying step for these sauce samples.[/SIZE]
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[SIZE=10.5pt]I've done some HPLC/LCMS work and I would probably recommend taking samples and grinding them as finely as possible, adding a solvent with vigorous mixing (ethanol, acetonitrile, etc.), using a centrifuge to separate the solid particulates, and collecting the solvent.[/SIZE]
[SIZE=10.5pt] [/SIZE]
[SIZE=10.5pt]Would be interesting to see if these different methods had similar results. [/SIZE]

Thanks for posting that article, Voodoo 6.  I don't understand a lot of the technical jargon, but the basic explanations coincide with what labs have told me over the years.  I've also been told by various labs that do and those that don't do SHU testing, that there is some proprietary work going on behind the scenes as to their processes and methods.  Some labs are set up for capsaicin testing, some are not. 
 
Interesting note- the heat of the sample is referred to as pungency ​by the ASTA, a term that is also used for spices like garlic, cinnamon and paprika.  It is only with chiles that the pungency rating gets correlated back to the Scoville Heat Units.