AW: [ RadSafe ] LSC Method Assistance Needed - CO2

[Franz Schönhofer]

Hi Barbara,

Though I do rather rarely LSC counting nowadays (I am retired, but stil
cooperate with some foreign institutes) I feel addressed by your remark! I
have been working with LSC for more than 30 years and though I have not
actively involved in measurement of C-14 in breath I have some knowledge
about different techniques. (I have been determining C-14 in alcohol and in
waste water from nuclear research reactors.)

You have not mentioned the goal of the analysis, but I assume it might be
the Campylobacter-C-14Urea-test. I would as a principle recommend for
anybody searching for something to consult firsthand Google. Out of
curiosity I did it and found some interesting papers. (Campylobacter, C-14,
LSC.) One was a paper by a Perkin-Elmer employee, which gives a procedure
and names a cocktail. The link which Roy Herren gave to Perkin Elmer did not
work. I know for sure, that one of the most important sales argument of the
instrument "Triathler" of Hidex Oy (Turku, Finland) was the use for the
Campylobacter test. I do not remember the details. Unfortunately I have not
found any literature at their website (www.hidex.com) now. There is a hint
on this website for a new representative in the USA. You may contact them or
the main office in Turku - if you do the latter, you may mention my name, I
know personally Jukka Haaslahti, the owner and his son Ville. 

I have hardly ever mixed cocktails (neither alcoholic ones nor LSC) myself.
There are several reasons: "Time is money", the chemicals may vary in their
quality and purity, which is not (or should not be) the case in ready-to-use
cocktails. For different applications in ultra low-level counting I have
tested up to 20 commercial cocktails. The topic of "nasty chemicals" is not
the main argument - a chemist should know how to use toxic substances
safely! The solvents used in modern  commercially available cocktails (like
DIN) are of course much "safer".

I hope I have been able to give you some hints, you are welcome if you have
further questions. 

Best wishes,

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 blreider at aol.com
Gesendet: Donnerstag, 07. Jänner 2010 16:07
An: radsafe at radlab.nl
Betreff: Re: [ RadSafe ] LSC Method Assistance Needed - CO2


Thanks to those of you who have responded, I think your inputs have been
helpful.  If anyone else who does a lot of LSC counting has additional input
we would love to hear from you!

Barbara Reider, CHP






-----Original Message-----
From: blreider at aol.com
To: radsafe at radlab.nl
Sent: Wed, Jan 6, 2010 8:27 pm
Subject: [ RadSafe ] LSC Method Assistance Needed - CO2



One of my friends, a new HP, asked me if I could assist him in finding a
better 
ocktail for his SC work.  He writes:  "Our breath bioassay monitors 14CO2.
So 
e have a solution that we make, and we bubble the air from the balloons in
the 
olution to trap the co2 and count it on our LSC.  This has been done for a
long 
hile, but the mixture is made up of some nasty stuff, so I just want to see
if 
e 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 and
advice 
 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 and
advice 
 am sure he will appreciate it.
hanks in advance.
arbara Reider, CHP 

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