Liquid scint counting of urine

["Denis Rinkacs, Jr" <dr4i+@andrew.cmu.edu>]

Good Afternoon,

I have access to a Beckman LS7000 LSC.  I counted my urine by the
following method:

1 ml of urine to 10 ml of Ecolite cocktail; dark dampened for approx. 5
hrs;  counted on prg 4, channel 1 (lower limit - 0 and upper limit -
655) for 10 min.  Used 10 ml of cocktail for background.

Results: Background 25 cpm; sample 175 cpm/ml, H# 139 and efficiency of
89% or 166 dpm/ml.  If there is 1400 ml/day of urine voided - then
166dpm/ml x 1400ml/day = 235955dpm/day (0.11 micro curies per day) of
activity in my urine? 

Is there documentation anywhere that would tell me what gross beta would
be for urine? I'm looking for baseline data to subtract from samples
counted using the stated mini-procedure.

the reason I'm asking this is to see if it is worthwhile to collect and
count bioassays (urine) via a liquid scint counter as a quick go no-go
test for further investigation (ie sending samples (spending money) to a
lab certified to do bioassays for different isotopes).

thanks for any and all assistance in this (possibly futile) matter

Denny
RSO, Carnegie Mellon University
dr4i@andrew.cmu.edu
412-268-3221
412-268-3206 fax