Peeters T L, Vantrappen G R
Clin Chem. 1977 Jun;23(6):1052-3.
We discuss the suitability of some radioactive isotopes as volume markers in radioimmunoassays, from a radiochemical point of view. For three eligible isotopes (22Na, 60Co, and 75Se) we studied the concentration of the marker in the precipitate formed in the separation phase of radioimmunoassays. For all those kinds of separations tested (charcoal, ammonium sulfate, polyethylene glycol, and ethanol), binding or coprecipitation was virtually absent or negligible with 22Na but 75Se was strongly concentrated in the precipitate. Concentration of 60Co occurred only with charcoal and ethanol precipitation. Because heavy metals tend to bind to serum proteins, we conclude that of all radioactive isotopes commercially available only 22Na should be used in radioimmunoassays with nonimmunological separation methods.
从放射化学的角度，我们讨论了一些放射性同位素作为放射免疫分析中体积标记物的适用性。对于三种合格的同位素（22Na、60Co和75Se），我们研究了放射免疫分析分离阶段形成的沉淀物中标记物的浓度。对于所测试的所有分离类型（活性炭、硫酸铵、聚乙二醇和乙醇），22Na几乎不存在结合或共沉淀现象，或可忽略不计，但75Se在沉淀物中强烈富集。60Co仅在活性炭和乙醇沉淀时出现富集。由于重金属倾向于与血清蛋白结合，我们得出结论，在所有市售的放射性同位素中，只有22Na应用于非免疫分离方法的放射免疫分析。
