Rapid determination of plutonium in urine by ultrafiltration

Abstract

A rapid and inexpensive method for the determination of plutonium in urine has been developed. The principle depends upon separating macromolecular plutonium species by ultrafiltration and directly counting the material retained on the membrane. Using a scintillation detection system having a background of 0·006 ± 0·002 cpm (2 S.D.) and a sample counting time of 8 hr, the limit of detection (background ± 2 standard deviations) was equivalent to 0·11 dpm in a 24-hr urine sample. The net alpha activity of ultrafiltered material from the urine of humans unexposed to plutonium was 0·008 ± 0·008 cpm in a 24-hr sample. Because the reference level for plutonium, 0·44 dpm for a 24-hr sample, is exceeded only occassionally the method can be used without modification as an effective screening procedure. For the few samples of alpha activity greater than the reference level a simple additional stage can be used to characterize the alpha radiation.