Katharine Thayer wrote:
>
> MARTINM wrote:
> >
> > "In short, I think the purity of PVA, especially in terms of per cent
> > -COOH in the long alcohol, kinda like mixed poly(vinyl alcohol/acrylic
> > acid) is the source of disagreeing results. Another possible impurity
> > might be a redox catalyst, like some transition metals. I think
> > Mannivanan, Lafond, and those groups pay some attention to the purity
> > of PVA, and some other studies were done with PVA containing some
> > impurities. One of their study says Cr(V) is stable in PVA. Then, it's
> > natural not to see Cr(III) absorptions right away."
>
> So if I understand you right, you think the reason Mannivannan couldn't
> assess whether the chromium was complexed with the PVA is because of
> impurities in the PVA? Could you expand on the last two sentences?
> Martin may see, but I don't quite.
Never mind, I do see; at least I see why it would make sense that you
wouldn't see Cr(III) absorptions right away if Cr(V) is stable in PVA.
What I don't understand now is why you attribute the discrepancy to
impurities if Mannivanan pay attention to purity; in that case I would
think you would be more inclined to credit Mannivannan's result than
less inclined. I'm not finding fault, I'm just trying to understand.
Katharine
Received on Fri May 21 06:15:15 2004
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