Bioassay technique is used for the estimation of actinides present in the body based on the excretion rate of body fluids.
For occupational radiation workers urine assay is the preferred method for monitoring of chronic internal exposure. Determination
of low concentrations of actinides such as plutonium, americium and uranium at low level of mBq in urine by alpha-spectrometry
requires pre-concentration of large volumes of urine. This paper deals with standardization of analytical method for the determination
of U-isotopes in urine samples using anion-exchange resin and 232U tracer for radiochemical recovery. The method involves oxidation of urine followed by co-precipitation of uranium along
with calcium phosphate. Separation of U was carried out by Amberlite, IRA-400, anion-exchange resin. U-fraction was electrodeposited
and activity estimated using tracer recovery by alpha-spectrometer. Eight routine urine samples of radiation workers were
analyzed and consistent radiochemical tracer recovery was obtained in the range of 51% to 67% with a mean and standard deviation
of 60% and 5.4%, respectively.