From: Georgi Ginev (georgi_ginev$##$yahoo.com)
Date: Fri Oct 18 2002 - 05:03:08 EDT
hi,
DSC is questionable method for this compound. PTCDA
has three crystal forms. So from DSC I will not know
whatever the peaks are from crustallization,
transformation of one form to another or from
impurities. It have to be combined with temperature
dependence XRay.
The people which made MS for me said me that I can not
extract purity from this type of data. For the
compounds with relatively high number of C atoms, our
apparatus can make a big error.
You can see a example MS here:
http://www.aist.go.jp/RIODB/SDBS/sdbs/owa/sdbs_sea.cre_frame_select?imgdir=ms&fname=MSNW8123&sdbsno=13598
On our NMR aparatus is not possible to measure the
solution with low concentration and NMR will give
error about 5% in the purity.
Other idea is FT-IR, but we did not try yet.
Best wishes.
Georgi
--- chemelf$##$gmx.net wrote:
> What about DSC? Make DSC before and after. Then you
> may try MS, NMR in
> d6-DMSO. A lot of things that you know, of course.
> You may transform
> your compound to another one that is more easy
> characterized if it
> possible.
>
> Ilfir.
> http://chemelf.tripod.com
>
>
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