The measurement of radioactive sulphur (35S) in biological material

Abstract

A sample of the material was oxidized by the Carius method and the sulfate was precipitated as benzidine sulfate. The radioactivity of the benzidine sulfate was measured in an. ionization chamber operated in conjunction with an FP-54 valve amplifying system and a galvanometer and was compared with the activities of samples of benzidine sulfate prepared from the parent radioactive specimen. When mustard gas prepared from radioactive sulfur was analyzed in the presence of biological material (skin, leg muscle, liver, blood, feces, or urine) by this method, the mean recovery of S35 was 99%, and the standard deviation of a single measurement from the mean was 2.8%.