Neutron Activation Analysis of Arsenic, Antimony and Cadmium in Metallic Zinc

Abstract

Studies were made to establish a rapid and simple radiochemical procedure for the determination of antimony, arsenic and cadmium in metallic zinc by neutron activation analysis. The procedure involves short time irradiation, rapid dissolution of the target and one-step separation of each nuclide (¹²²Sb, ⁷⁶As and ^111mCd) from the target nuclides (⁶⁵Zn and ^69mZn) .
The irradiated target was rapidly dissolved with hydrochloric acid in the presence of potassium bromate. ¹²²Sb was separated by DEHPA extraction from concentrated hydrochloric acid and ⁷⁶As by As₂S₃ precipitation in a 6M hydrochloric acid solution. ^111mCd was freed from zinc activities by ethyl ether extraction of zinc thiocyanate complex. About half an hour was enough to separate each nuclide from the target. The limits of detection are ca. 30 ppb for antimony, ca. 15 ppb for arsenic and ca. 120 ppb for cadmium by short time irradiation of small amounts of the zinc sample.