Electrodialytic Handling of Radioactive Metal Ions for Preparation of Tracer Reagents

Abstract

Radioactive metals are applied in biochemistry, medical diagnosis such as positron emission tomography (PET), and cancer therapy. However, the activity of radioisotopes exponentially decreases with time; therefore, rapid and reliable probe preparation methods are strongly recommended. In the present study, electrodialytic radioactive metal ion handling is studied for counter ion conversion and in-line probe synthesis. Presently, counter ion conversion and probe synthesis are achieved by evaporative dryness and solution mixing, respectively. Evaporative dryness is time-consuming and is a possible process that can lead to loss of radioactive metal ions. Mixing of solutions for synthesis makes dilution and undesirable effects of counter ion on the synthesis. An optimized electrodialytic flow device can transfer a radioisotope, 64Cu2+, with high recovery from HCl matrices to HNO3 (∼100%). Matrices can also be transferred into acetic acid and citric acid, even though the concentration of the metal ion is at the picomolar level. The ion transfer can also be achieved with simultaneous counter ion conversion, complex synthesis, and enrichment. When the ligand was dissolved in an acceptor solution, the transferred metal ions from the donor were well mixed and formed a complex with the ligand in-line. The efficiency of the synthesis was ∼100% for 1.0 pM 64Cu. A relatively larger donor-to-acceptor flow rate can enrich the metal ion in the acceptor solution continuously. The flow rate ratio of 10 (donor/acceptor) can achieve 10 times enrichment. The present electrodialytic ion handling method can treat ultra-trace radioisotopes in a closed system. With this method, rapid, effective, and safe radioisotope treatments were achieved.

Electrodialytic Enrichment and Matrix Conversion for the Determination of Trace Metals in Ultra-Pure Water

“…For these reasons, in a typical analysis, the EED transferred the analyte ions from the UPW sample to an acidic solution suitable for ICP–MS analysis. This treatment both increased the concentrations of analytes and provided a uniform solution matrix, as detailed in a previous publication . It should also be noted that As, Se, and V, highlighted in red in Figure S3, were not detected in the EED-enriched solution because the four-layer ITD was only able to transfer cations and these elements were in the form of oxo-anions.…”

“…This treatment both increased the concentrations of analytes and provided a uniform solution matrix, as detailed in a previous publication. 14 It should also be noted that As, Se, and V, highlighted in red in Figure S3 , were not detected in the EED-enriched solution because the four-layer ITD was only able to transfer cations and these elements were in the form of oxo-anions. The remaining nine elements (highlighted in blue in Figure S3 ) were difficult to analyze either by direct injection or after enrichment by the EED.…”

Electrodialytic Universal Synthesis of Highly Pure and Mixed Ionic Liquids

“…These channels were subsequently separated with AEMs (Figure , SELEMION AMVN, ) . Similar electrodialytic devices were used for ion transfer in our previous works. − …”

Highly Efficient Separation of Ultratrace Radioactive Copper Using a Flow Electrolysis Cell

“…Our group recently developed a drug synthesis process using an electrodialytic ion-transfer device (ITD). 22 This device was first developed by Ohira et al 23 and has been applied to extract inorganic anions, 24 enable chromium speciation, 25 and separate weak acids. 26 The ITD was used to demonstrate in-line probe synthesis using DOTA and 1.0 pmol/L 64 Cu 2+ .…”