摘要:
本文报道了以二碘甲腺原氨酸(3,5-T_2)为起始物,用碘-131、碘-125标记制备三碘甲腺原氨酸(T_3),用自身置换法和放射免疫分析法测定~(125)I-T_3的比活度,从而求出Na~(125)I的比活度,为测量放射性碘的比活度提供了一种新的途径。同时,用碘离子选择性电极测定Na~(125)I、Na~(131)I溶液中总的碘含量,放射性活度用经过校准的4π电离室测量装置测定,求出放射性碘的比活度。不同的方法所测得的结果相近。国产Na~(125)I、Na~(131)I制剂中碘-125、碘-131的丰度分别为50％和6％左右。本文还讨论了Na~(125)I、Na~(131)I制剂中碘的来源。
Abstract:
In this work, 3,5-L-diiodothyronine as a starting material, 125I-L-triiodothyronine (125I-T3) and 131I-L-triiodothyronine (131I-T3) are prepared, and the specific activity of 125I-T3 is measured by self-displacement and from the standard curve obtained by 131I-T3 for the radioimmunoassay of 125I-T3. The specific activity of Na125I solution can be calculated from that of 125I-T3. This is a new method for the determination of the specific activity of radioiodine. Meanwhile, the total iodide content of the Na125I, Na131I solutions is measured via an iodide selective electrode, and the radioactivity of the Na125I, Na131I solutions via a calibrated 4π-ionazation chamber respectively. Thereby the specific activities of radioiodines can be calculated. The results obtained by different methods agree fairly well. The abundances of iodine-125 and iodine-131 in the Na125I and Na131I solutions are about 50% and 6% respectively. The sources of iodine in the samples are also discussed.
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