Crown ether–ionic liquid-based extraction chromatographic resin for separation of 90Y from 90Sr

Sorption Characteristics and Chromatographic Separation of 90Y3+ from 90Sr2+ from Aqueous Media by Chelex-100 (Anion Ion Exchange) Packed Column

There is growing demand for separation of 90Y carrier free from 90Sr coexisting to produce high purity 90Y essential for radiopharmaceutical uses. Thus, in this context the sorption profiles of Y3+ and Sr2+ from aqueous solutions containing diethylenetriaminepenta acetic acid (DTPA), ethylenediaminetetra-acetic acid (EDTA), acetic acid, citric acid, or NaCl onto Chelex-100 (anion ion exchange) solid sorbent were critically studied for developing an efficient and low-cost methodology for selective separation of Y3+ from Sr2+ ions (1.0 × 10-5 M). Batch experiments displayed relative chemical extraction percentage (98 ± 5.4%) of Y3+ from aqueous acetic acid solution onto Chelex-100 (anion ion exchanger), whereas Sr2+ species showed no sorption. Hence, a selective separation of Y3+ from its parent 90Sr2+ has been established based upon percolation of the aqueous solution of Y3+ and Sr2+ ions containing acetic acid at pH 1-2 through Chelex-100 sorbent packed column at a 2 mL min-1 flow rate. Y3+ species were retained quantitatively while Sr2+ ions were not sorbed and passed through the sorbent packed column without extraction. The sorbed Y3+ species were then recovered from the sorbent packed column with HNO3 (1.0 M) at a 1.0 mL min-1 flow rate. A dual extraction mechanism comprising absorption associated to "weak-base anion exchanger" and "solvent extraction" of Y3+ as (YCl6)3- and an extra part for "surface adsorption" of Y3+ by the sorbent is proposed. The established method was validated by measuring the radiochemical (99.2 ± 2 1%), radionuclide purity and retardation factor (Rf = 10.0 ± 0.1 cm) of 90Y3+ recovered in the eluate. Ultimately, the sorbent packed column also presented high stability for reusing 2-3 cycles without drop in its efficiency (±5%) towards Y3+ uptake and relative chemical recovery. A proposed flow sheet describing the analytical procedures for the separation of 90Y3+ from 90Sr2+ using chelating Chelex 100 (anion exchange) packed column is also included.

An overview of automated flow systems for total and isotopic analysis of strontium and yttrium in samples of environmental interest

Due to the different uses of radioactivity during the last decades, there has been an increase in the concentration of natural and artificial radionuclides in the environment. This, along with some accidents with a high affect public opinion (for example, Chernobyl and Fukushima), have led to the growth and establishment of environmental radioactivity monitoring programs. Currently, trends in legislation and research are focused on the development of accurate, precise, reliable and fast analytical methods with low limits of detection (LOD) for radionuclides determination, such as strontium and yttrium, in environmental samples. In this paper, two comprehensive reviews and four automated analytical systems for total and isotopic determination of yttrium and strontium are presented. The developed methods have been applied in the analysis of environmental samples with low concentrations of these analytes. These methodologies have been automated by exploiting flow analysis techniques, such as multi-syringe flow injection analysis (MSFIA), Sequential injection analysis (SIA) and laboratory-on-valve (LOV) systems, achieving a minimal handling and low consumption of samples and reagents, a significant reduction in waste generation and a high frequency of analysis. In the developed methodologies, some spectrometric methods such as ICP-OES and ICP-MS have been implemented as detection techniques instead of radiometric detectors obtaining a fully automated, low-cost and fast yttrium and strontium determinations.

Studies on purification of 89Sr from irradiated yttria target by multi-column extraction chromatography using DtBuCH18-C-6/XAD-7 resin

89Sr is being produced using yttria target via the nuclear reaction 89Y(n,p)89Sr in Fast Breeder Test Reactor (FBTR), Kalpakkam. The isotope 89Sr is a pure beta emitter with a half-life of 50.53 days which is useful mainly for bone pain palliation in patients with bone metastases. The existing method for processing the irradiated yttria target to obtain the pure 89Sr source involves separation of the bulk yttrium target by solvent extraction using TBP-HNO3 followed by purification of 89Sr source by cation exchange chromatography technique using Dowex resin. The study described here involves the selective extraction and purification of 89Sr by multi-column extraction chromatography technique using the Sr-specific crown ether, DtBuCH18C6 (CE) coated onto an XAD-7 resin matrix for superior separation and increased yield compared to single column technique. The 89Sr source thus purified from the irradiated yttria target is free from other radionuclidic impurities produced during the target irradiation i.e. 88Y, 65Zn, 139,141Ce, 154Eu and 160Tb.