Plutonium in human urine: Normal levels in the US public. 1991 Annual report, Volume 2

A neutron induced fission track method was successfully developed for assaying 239Pu in human urine with a detection limit below 20 aCi/sample. The technique involves the co-precipitation of 239Pu with rhodizonic acid, separation of 239Pu from potentially interfering natural uranium and other inorganic materials by ion-exchange techniques, collection of the sample onto lexan detectors, irradiation of sample in MIT reactor at a fluence of 1.1 x 1017 n/cm2, etching of the lexan slide and counting the track either manually or by some automated counting system