Activation Analysis of Chlorine, Bromine and lodine in Biological Materials

• Published in: RADIOISOTOPES Vol. 19; no. 3; pp. 129 - 135
• Main Authors: ISHII, Daido, NAKASHIMA, Masahiko
• Format: Journal Article
• Language: Japanese; English
• Published: Japan Radioisotope Association 1970
• ISSN: 0033-8303; 1884-4111
• DOI: 10.3769/radioisotopes.19.3_129

A method has been developed for the determination of trace amounts of chlorine, bromine, and iodine in biological materials. After thermal neutron irradiation of the sample for 20 minutes at a flux of 2×1013n⋅cm-2⋅sec-1, followed by rapid chemical separation, chlorine, bromine and iodine were determined by gamma-ray spectrometry. The sample was transferred to the distillation flask together with 0.2mM each of KCl, KBr and KI carrier. While being heated and made bubbles with the air stream, it was decomposed by the conc. HNO3 and conc. H2SO4 mixture. Iodine and bromine were distilled at this step. Potassium permanganate solution was then added to the flask to form chlorine. During the process the distillate was absorbed in the Na2SO3 solution. Then for the determination of iodine, accurate 0.1 mM of AgNO3 was added to the solution and 0.1mM of negatively charged colloidal pure AgI was formed. It was precipitated by Al (NO3) 3 9 H2O and faltrated. Immediately the gamma activity of 128I was counted. Then for the determination of others the excess of AgNO3 was added to the filtrate, the precipitate containing AgI, AgBr and AgCl was filtrated, immediately the activity of 38Cl was counted, and after the 38Cl decay, the activity of 82Br was counted. The gamma activity of the sample was counted with a 3 in. φ×3 in. NaI (Tl) crystal connected to a TMC 256 channel pulse height analyzer. The chemical yields were about 100 percent with halogens, and the separation time was 30-50 minutes for iodine. The isolated precipitates of AgI were extremely pure.