radsafe: tritium analysis of urine by LSC

["Donivan Porterfield, LANL NMT-1" <dporterfield@lanl.gov>]

>Date: Fri, 1 May 1998 14:30:50 -0500 
>From: "Price, Carol J" <PriceCarolJ@exchange.uams.edu>
>To: "'radsafe@romulus.ehs.uiuc.edu'" <radsafe@romulus.ehs.uiuc.edu>
>
>Can anyone help me with the best way to measure H-3 in urine?

I think most mix the as-is urine with scintillation cocktail and 
count.  The proportions of urine and cocktail as well as count time 
and ROI depending on the cocktail, counter background and efficiency,
and desired detection limit.

There are some that use distillation to isolate the water from the 
urine before counting.  The urine matrix bringing some quench and
luminescence issues that the distillation removes.  I'm not sure if
there might also be some issue of tritium as HTO versus organically
bound tritium (OBT).

It's my impression that the small tritium decay energy and relatively
short biological half-life minimize the activity to dose conversion.
Thus there is not typically the drive to lower bioassay detection 
limits as there are for some alpha emitters.


Donivan Porterfield              (505) 667-4710
Los Alamos National Laboratory   (505) 665-5982 fax
MS K484, NMT-1 (Analytical Chemistry)
Los Alamos, NM  87545             dporterfield@lanl.gov