[Ifeffit] Questions on EXAFS

Matt Newville newville at cars.uchicago.edu
Sun Mar 16 15:51:22 CDT 2008


On Sun, Mar 16, 2008 at 3:07 PM, Rajasekaran S <sgoofy8 at gmail.com> wrote:
> I have a couple of questions on the use of EXAFS:
> 1. How sensitive is EXAFS/XANES in determining ~ couple of ppm (up to
> 100ppm) of halogen content in solid content?

It depends, somewhat on what you mean.  Probably the simplest answer
is: EXAFS/XANES is terrible at telling the halogen content in "solid
content". EXAFS/XANES studies one selected element, ignoring those
that are not directly bound to the element selected.   That it, it
would be pretty much useless at telling a Cl/Br ratio.

You may want to look into X-ray Fluorescence analysis, which can
non-destructively determine elemental abundances.

On the other hand, EXAFS/XANES can successfully measure the bonding of
Cl and Br when they are at 100ppm or so (perhaps less) in solid
content.  In my experience, EXAFS/XANES on elements at concentrations
of a few ppm is very challenging, though it does depend what the rest
of the system is.

> 2. Also, are there lab-scale EXAFS/XANES equipments available towards this?
> Anyone working on lab-scale equipments?

There are lab-based EXAFS/XANES systems.  I believe Rigaku sells
machines for laboratory EXAFS.  They may be the only company to do so.

Hope that helps,


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