Paul Sumana, Pandey Ashok K, Kumar Pranaw, Kaity Santu, Aggarwal Suresh K
Fuel Chemistry Division, ‡Radiochemistry Division, and §Radiometallurgy Division, Bhabha Atomic Research Centre (BARC) , Trombay, Mumbai-400 085, India.
Anal Chem. 2014 Jul 1;86(13):6254-61. doi: 10.1021/ac501509t. Epub 2014 Jun 19.
Monitoring of actinides with sophisticated conventional methods is affected by matrix interferences, spectral interferences, isobaric interferences, polyatomic interferences, and abundance sensitivity problems. To circumvent these limitations, a self-supported disk and membrane-supported bifunctional polymer were tailored in the present work for acidity-dependent selectivity toward Pu(IV). The bifunctional polymer was found to be better than the polymer containing either a phosphate group or a sulfonic acid group in terms of (i) higher Pu(IV) sorption efficiency at 3-4 mol L(-1) HNO3, (ii) selective preconcentration of Pu(IV) in the presence of a trivalent actinide such as Am(III), and (iii) preferential sorption of Pu(IV) in the presence of a large excess of U(VI). The bifunctional polymer was formed as a self-supported matrix by bulk polymerization and also as a 1-2 μm thin layer anchored on a microporous poly(ether sulfone) by surface grafting. The proportions of sulfonic acid and phosphate groups in both the self-supported disk and membrane-supported bifunctional polymer were found to be the same as expected from the mole proportions of monomers in polymerizing solutions used for syntheses. α radiography by a solid-state nuclear track detector indicated fairly homogeneous anchoring of the bifunctional polymer on the surface of the membrane. Pu(IV) preconcentrated on a single bifunctional bead was used for determination of the Pu isotopic composition by thermal ionization mass spectrometry. The membrane-supported bifunctional polymer was used for preconcentration and subsequent quantification of Pu(IV) by α spectrometry using the absolute efficiency at a fixed counting geometry. The analytical performance of the membrane-supported-bifunctional-polymer-based α spectrometry method was found to be highly reproducible for assay of Pu(IV) in a variety of complex samples.
采用精密传统方法监测锕系元素时，会受到基体干扰、光谱干扰、同量异位素干扰、多原子干扰以及丰度灵敏度问题的影响。为克服这些限制，本研究制备了自支撑圆盘和膜支撑双功能聚合物，用于对 Pu(IV) 的酸度依赖性选择性。结果发现，双功能聚合物在以下方面优于含磷酸基团或磺酸基团的聚合物：(i) 在 3 - 4 mol L(-1) HNO3 中具有更高的 Pu(IV) 吸附效率；(ii) 在三价锕系元素如 Am(III) 存在下对 Pu(IV) 进行选择性预富集；(iii) 在大量过量的 U(VI) 存在下优先吸附 Pu(IV)。双功能聚合物通过本体聚合形成自支撑基体，也通过表面接枝形成锚定在微孔聚醚砜上的 1 - 2 μm 薄层。发现自支撑圆盘和膜支撑双功能聚合物中磺酸基团和磷酸基团的比例与用于合成的聚合溶液中单体的摩尔比例预期相同。通过固态核径迹探测器进行的 α 射线照相表明双功能聚合物在膜表面的锚定相当均匀。预富集在单个双功能微珠上的 Pu(IV) 用于通过热电离质谱法测定 Pu 同位素组成。膜支撑双功能聚合物用于预富集，并随后通过在固定计数几何条件下使用绝对效率的 α 能谱法对 Pu(IV) 进行定量。发现基于膜支撑双功能聚合物的 α 能谱法的分析性能在分析各种复杂样品中的 Pu(IV) 时具有高度重现性。
