A simple method has been developed for estimating Ru-106 in urine. Uri
ne samples spiked with 350 Bq of Ru-106 and 200 mug of ruthenium carri
er were initially oxidized using an HNO3-H2O2 mixture. Attempts to rec
over ruthenium by various preconcentration methods after the initial o
xidation resulted in recoveries ranging from 10-54% depending on the e
xperimental conditions. For near quantitative recoveries, the organic
matter in urine was completely destroyed by wet ashing with HNO3-H2O2
(method A) or HNO3-H2O2 followed by H2SO4 treatment (method B). The ru
thenium was oxidized to RuO4 using potassium periodate and allowed to
react in situ with polyethylene powder. The polyethylene powder was se
parated, washed and its beta activity was counted. The recovery of rut
henium was 86.9 +/- 4.6% (RSD 5.3%) in method A; and 94.4 +/- 2.6% (RS
D 2.8%) in method B. The minimum detection limit achieved was 0.59 Bq/
dm3. Interferences due to Cs-137 and Sr-90 were studied.