AW: [ RadSafe ] LSC Method Assistance Needed - CO2

Fri Jan 8 18:08:48 CST 2010

Hi, here I am.....(again).

I know a little about LSC, but would not claim that I know everything.
Though I am happy that I could work during the last years at least
temporarily with LSC (I am retired), this was mostly in the NORM field.
However I am satisfied that I remember quite a lot from previous times. So I
remember the word "Hyamine hydroxide" both as a solubilizer of tissue and an
absorption reagent for CO2, used primarily in sample oxidiser cocktails.
Please check at Google for "sample oxidizer cocktails" (PerkinElmer will
show up) and "Hyamine hydroxide 10-X", try also "breath test" or
"Campylobacter C-14" or similar. There is a lot there.

It seems to me that the tests for Campylobacter is more or less a
qualitative test - if this "beast" is present it will split C-14-urea and
produce C-14-O2, if not, there will be no signal of C-14O2. Therefore it
seems to me that no elaborate calibrations are necessary and since the
adminstered C-14 activities are high no problems with LLD are encountered. 

All the elaborate thoughts about absorption efficiency of different
chemicals are really not necessary in this case. 

Of course those considerations play a big role, when low C-14 concentrations
for instance in the environment are of concern. LiOH has been found to have
advantages over other absorption hydroxides - but this is another story. 

Best regards to everybody,

Franz

Franz Schoenhofer, PhD
MinRat i.R.
Habicherg. 31/7
A-1160 Wien/Vienna
AUSTRIA

-----Ursprüngliche Nachricht-----
Von: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] Im Auftrag
von Thomas Johnston
Gesendet: Freitag, 08. Jänner 2010 05:29
An: blreider at aol.com
Cc: Daren.Perrero at illinois.gov; radsafe at radlab.nl
Betreff: Re: [ RadSafe ] LSC Method Assistance Needed - CO2

Hello,
I recommend works by Donald Horrocks, Yutaka Kobayashi and Franz Shoenhofer.
Among others that will be found in the References in the Works by these
pioneers in the field of LSC and Analysis.
I have done extensive work and research in sample preparation methodology
and analysis, specifically for LSC counting applications.

Pick an isotope, pick a sample preparation method; and, in all likelihood,
this sample has been prepared for analysis in an LSC.

You may have to look a bit further to find these references. Can you get to
a good Medical Center library?
Are you familiar with Google Scholar?  The early operating manuals for LSC's
coverd these Works and often included excepts in their Appendix.
The early LSC 'scientific community' User Meetings Proceedings
publications often covered tremendous depth and breadth with regards to
these topics of sample prep and analysis, including details for these
various methods.  Unfortunately, much of my physical library was
lost/destroyed in recent tropical storms/hurricanes in the Gulf Coast region
of the USA.

Often, the LSC vendors will have available these timeless references that
can be retrieved from their Archives for great use Today!!!
I hope I may be of assistance with your work?

Best wishes,
Thomas Johnston
Health Physicist
NIST NCNR

On Thu, Jan 7, 2010 at 9:53 PM, <blreider at aol.com> wrote:

>
> Thanks for your input and query Darren and Dave.
>
> Dave:  I do think you have a valid question - when doing any procedure a
> calibration should quantify all aspects of the method used, not just the
> count to disintegrations ratio.  I have not used this method for bioassay
> myself (this really was a question from someone else) so perhaps others
have
> the answer about quantification of losses.
>
> I have witnessed transport of tritium through just about any o-ring in
> creation.  It does take some time though, and I would think tritium
exchange
> is a much faster exchange than C with the C of rubber.  Don't know about
> other mechanisms such as rubber pore sixe issues but if not held for long
> perhaps this method of collection does not create big errors or losses.
>
> That said, iodine adsorbing on the walls of collection tubes from stack
> monitors seems to be always a problem.  Results resulting from isotopic
> isokinetic sampling is in many cases lower than the actual concentrations.
>
> 2 cents!
>
> Barbara Reider, CHP
>
>
>
>
> -----Original Message-----
> From: neildm at id.doe.gov
> To: Daren.Perrero at illinois.gov; blreider at aol.com; radsafe at radlab.nl
> Sent: Thu, Jan 7, 2010 7:25 pm
> Subject: RE: [ RadSafe ] LSC Method Assistance Needed - CO2
>
>
> I just noticed something about the process outlined in the request.
> erhaps I am making an assumption, but use of a rubber balloon for
> ollection of a sample analyzed for CO2 has the confounding factor that
> O2 will dissolve through rubber and escape, or so I understood.
> Wrong?  Not Applicable?
> Just a comment.
> Dave Neil
> -----Original Message-----
> rom: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On
> ehalf Of Perrero, Daren
> ent: Thursday, January 07, 2010 3:27 PM
> o: blreider at aol.com; radsafe at radlab.nl
> ubject: RE: [ RadSafe ] LSC Method Assistance Needed - CO2
> In a previous life in a land far far away, we conducted similar tests in
> he same manner on respired air for the presence of H-3.  Our method
> imply involved passing the respired air through several loops of super
> ooled tubing immersed in liquid nitrogen.  Thus we were able to avoid
> color quenching' and nasty issues associated with other bodily fluids
> ince the collection/extraction solutions we gathered were essentially
> ll water.  After that we were able to pick and choose our scintillation
> ocktails based on their ability to deal with aqueous solutions for
> aximum efficiency.
> The opinions expresses are mine, all mine.....
> 'm with the government and I'm here to help you (ack!)
> aren.perrero(a)Illinois.gov
> -----Original Message-----
> rom: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On
> ehalf Of blreider at aol.com
> ent: Wednesday, January 06, 2010 7:27 PM
> o: radsafe at radlab.nl
> ubject: [ RadSafe ] LSC Method Assistance Needed - CO2
>
> One of my friends, a new HP, asked me if I could assist him in finding a
> etter cocktail for his SC work.  He writes:  "Our breath bioassay
> onitors 14CO2.  So we have a solution that we make, and we bubble the
> ir from the balloons in the solution to trap the co2 and count it on
> ur LSC.  This has been done for a long while, but the mixture is made
> p of some nasty stuff, so I just want to see if we can do better."
> The method they use a toluene based cocktail:  "solution that contains
> oluene,sodium hyrdroxide, trimethylbenzene, and methyl glycol."
> t has been a long time since I did LSC so if you have any experience
> nd advice I am sure he will appreciate it.
> hanks in advance.
> arbara Reider, CHP
> It has been a long time since I did LSC so if you have any experience
> nd advice I am sure he will appreciate it.
> hanks in advance.
> arbara Reider, CHP
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