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Thu, 23 Apr 2020 08:03:49 -0300 |
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Hi Richard (Dick),
I'm really pleased to talk to all you guys in this forum... I really
appreciate all high-level discussions and knowledge sharing here. It is
interesting how our reality with AHB is a little bit different from
yours... :)
*"Is the LC column used a size exclusion resin?"*
Ion exchange is most commonly used.
*" Second, is it fair to look at the reported values and say there is
pretty strong evidence that this particular sample in almost all bee keeper
added sugar with only perhaps 10 or 20% actual honey present? *
IRMS has evolved to include chromatographic separation. Before the
"separation era" results were from "total sugar content" and inferences on
% adulteration were very difficult. Currently in LC-IRMS you have an actual
chromatogram (peak areas) but still limitations on % adulteration. With
fraud becoming more sophisticated, LC-IRMS tends to be replaced by NMR.
*Also, why is Beltsville reporting four significant figures when the
cited paper pretty clearly indicates that three significant figures are the
most justified?*
No idea here. Perhaps an automated software calculation and report
generation...
*Do you care to comment on other techniques such as NMR that may make such
clever cheating a lot tougher?*
No doubt here that NMR has set a new standard. Bruker already has an
automated solution for that called FoodScreener and a humongous honey
database (Honey-Profiling). These database has thousands of honey
"fingerprints" for comparison on botanical and geographical origin. I'm not
recommending or advertising Bruker, just showing what's in the market.
Below you will find a link to a video about NMR use for honey testing and
how it helps and works (very informative). Of course, this is no cheap
solution. Hence, we still will see other simpler tests around. LC-IRMS
equipment it’s not cheap either, but certainly less than NMR.
https://www.youtube.com/watch?time_continue=1&v=L7hAi5sU2Ro&feature=emb_logo
Cheers to all
Felipe
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