What kind of plastic (polyethylene, pigmented, filled with silica or glass
???)
Why are you looking for Cr6/Cr3 ?
John Bondarowicz
Senior Chemist
S&C Electric Company
Chicago, Illinois, 60626-3997
phone: 773-338-1000x2428
fax: 773-381-4926
-----Original Message-----
From: Nimal De Silva [mailto:[log in to unmask]]
Sent: Wednesday, April 09, 2003 8:32 AM
To: [log in to unmask]
Subject: Re: Cr+6 Analysis
Dear Gaeho and all:
Even if you crush the sample, it is very unlikely that you will get a
quantitative extraction of Cr(+6) that is embedded in the material. If you
really want to determine only the Cr(+6), but not the total Cr, the trick
is, how to "digest" or "dissolve" the sample without changing the oxidation
state of Cr(+6) or the other species (eg. Cr(0), or Cr(+3)). Depending on
the nature of your "polymer material", if you can find a suitable organic
solvent (eg. CH2Cl2, etc..), you may dissolve the polymer in the solvent
and then do an alkaline solvent extraction, where
Cr(+6) will be extracted into the alkaline aqueous phase, perhaps along with
Cr(+3). Then you may be able to determine Cr(+6), separately from
Cr(+3) using a standard procedure specific to Cr(+6). There seems to be no
easy way out.
P.S. We can still receive some abstracts for ICASS2003 Conference
(http://www.icass2003.ca)
Regards,
Nimal
*********************************************************************
Dr. Nimal De Silva
Conference Chair, ICASS2003
49th International Conference on Analytical Sciences and Spectroscopy
Department of Chemistry Carleton University Ottawa, Ontario
Canada K1S 5B6
Tel: 613-520-2600 ext 2338
Fax: 613-520-2569
E-mail: [log in to unmask]
http://www.icass2003.ca
**********************************************************************
Gaeho Lee wrote:
> Thank you for the reply. However, we are still looking for the
> analytical method for Cr+6 analysis in polymer such as plastic.
>
> All of analytical method described here are mainly for environmental
> samples such as water, dust, soil and waste water. In this case, Cr+6
> is extracted
> from adsorbed and soluble forms of chromium compound by alkaline
> extraction.
>
> In order to analyze Cr+6 in plastic, plastic sample has to be crushed
> and grinded. As a result, the extraction efficiency by alkaline
> extraction would be dependent upon size and shape of sample.
>
> Is there any standard method for Cr+6 analysis in plastic ?
>
> Best Regards
>
> Gae H. Lee
> Department of Chemistry
> Chungnam University
> Dae Jeon, 305-764
> South Korea
>
>
>
>
>
>
>
> _________________________________________________________________
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