Re: Counting Tritium In Oil

[Franz Schoenhofer <schoenho@via.at>]

At 18:12 22.06.98 -0500, you wrote:
>Can anyone out there give me some help with H3 analysis (LSC) in
>lubricating oil?  I'm looking for a relatively simple method, if there is
>such a thing, as I don't have a fancy chem lab.  Would really like to hear
>methods that people have actually used so that I know it will work (given
>whatever limitations apply).  I can do simple distillation, and have access
>to most common solvents.  Any help would be greatly appreciated.
>
>
>Keith Welch
>Thomas Jefferson National Accelerator Facility
>Newport News VA
>welch@cebaf.gov
>Ph: (757)269-7212
>FAX:(757)269-5048
>
>-------------------------------

This depends on 

- the LLD you have to achieve
- on the concentration of tritium present
- the color of the oil.

If you have enough tritium present and/or the LLD to be achieved is very
high you may reduce quench considerably with strongly colored samples if
you dilute the oil with a solvent like toluene or xylene so it is only
slightly colored and then mix it directly with a xylene or toluene based
cocktail. Efficiency could be determined by adding an internal tritium
standard to a sample prepared the same way. 

We have used this "dilution" method for reducing the quench in the case of
urine samples - we diluted 1 ml of urine with 7 ml of water and then added
12 ml of a gelforming cocktail. The efficiency was satisfactory.

Good luck!

Franz


Franz Schoenhofer
Federal Institute for Food Control and Research
Department for Radiochemistry and Radioactivity of Food
Kinderspitalg. 15
A-1095 Vienna
AUSTRIA
tel.: +43-1-40491-520
fax.: +43-1-40491-540