Fan Xianfeng, Parker David J, Smith Mike D, Ingram Andy, Yang Zhufang, Seville Jonathan P K
School of Physics and Astronomy, The University of Birmingham, B15 2TT Birmingham, UK.
Nucl Med Biol. 2006 Oct;33(7):939-44. doi: 10.1016/j.nucmedbio.2005.08.001.
Separation of copper radioisotopes from a nickel target is normally performed using solvent extraction or anion exchange rather than using cationic exchange. A commonly held opinion is that cationic exchangers have very similar thermodynamic complexation constants for metallic ions with identical charges, therefore making the separation very difficult or impossible. The results presented in this article indicate that the selectivity of Chelex-100 (a cationic ion exchanger) for Cu radioisotope and Ni ions not only depends on the thermodynamic complexation constant in the resin but also markedly varies with the concentration of mobile H+. In our developed method, separation of copper radioisotopes from a nickel target was fulfilled in a column filled with Chelex-100 via controlling the HNO3 concentration of the eluent, and the separation is much more effective, simple and economical in comparison with the common method of anion exchange. For an irradiated nickel target with 650 mg Ni, after separation, the loss of Cu radioisotopes in the nickel portion was reduced from 30% to 0.33% of the total initial radioactivity and the nickel mixed into the radioactive products was reduced from 9.5 to 0.5 mg. This significant improvement will make subsequent labeling much easier and reduce consumption of chelating agents and other chemicals during labeling. If the labeled agent is used in human medical applications, the developed method will significantly decrease the uptake of Ni and chelating agents by patients, therefore reducing both the stress on human body associated with clearing the chemicals from blood and tissue and the risk of various types of acute and chronic disorder due to exposure to Ni.
从镍靶中分离铜放射性同位素通常采用溶剂萃取或阴离子交换，而非阳离子交换。一种普遍的观点认为，阳离子交换剂对于具有相同电荷的金属离子具有非常相似的热力学络合常数，因此使得分离非常困难甚至不可能。本文给出的结果表明，Chelex - 100（一种阳离子离子交换剂）对铜放射性同位素和镍离子的选择性不仅取决于树脂中的热力学络合常数，还会随着流动相H⁺浓度的显著变化而变化。在我们开发的方法中，通过控制洗脱液的硝酸浓度，在填充有Chelex - 100的柱中实现了从镍靶中分离铜放射性同位素，与常见的阴离子交换方法相比，该分离方法更有效、简单且经济。对于含有650毫克镍的辐照镍靶，分离后，镍部分中铜放射性同位素的损失从总初始放射性的30%降至0.33%，混入放射性产物中的镍从9.5毫克降至0.5毫克。这一显著改进将使后续标记更加容易，并减少标记过程中螯合剂和其他化学品的消耗。如果标记剂用于人类医学应用，所开发的方法将显著降低患者对镍和螯合剂的摄取，从而减少与从血液和组织中清除化学物质相关的人体压力以及因接触镍而导致各种急慢性疾病的风险。
