Determination of U and Th in urine by neutron activation

Urinalysis for natural U and Th was done by neutron activation. Percent recovery (+/- 1 sigma) was 80 +/- 20 for U and 80 +/- 10 for Th. The method is sufficiently sensitive to detect, in a 100-ml sample, less than 1 and 6 micrograms/l. of 232Th and 238U, respectively.