Attempts to understand potential deficiencies in chemical procedures for AMS
Attempts to understand potential deficiencies in chemical procedures for AMS
复制标题
DOI：
10.1016/j.nimb.2019.05.005
复制
发表时间：
2019-10-01
影响因子：
1.3
通讯作者：
Wetterich, Sebastian
中科院分区：
文献类型：
--
作者：
Merchel, Silke;Beutner, Sabrina;Wetterich, Sebastian
DREsden 加速器质谱 (DREAMS) 设施的一个主要研究重点是样品制备：内部和合作实验室。除了常规应用外，开发主要由用户的需求驱动，例如“新”放射性核素（例如短寿命的 Be-7）、来自新基质或较大样品量和较低浓度的放射性核素。在 BeO 用于 Be-7、Be-10、Al2O3 用于 Al-26、AgCl 用于 Cl-36、Fe2O3 用于 Fe-60 和锕系 AMS 靶材的化学制备中，我们研究并改进了大部分特定步骤：对于氧化物制备，建议老化数小时并两次冲洗氢氧化物，特别是 Be(OH)(2) 和 Al(OH)(3)，以防止最终制备步骤中的损失。冲洗新沉淀的氢氧化物可能造成高达 31% 的损失。对于 Al(OH)(3)，建议使用 H2O (pH5) 而非 pH8-9 冲洗，以进一步减少再溶解。对于 Fe-60 和共沉淀锕系元素（后者通过 U6+ 和 Er3+ 测试），漂洗过夜老化的 Fe(OH)(3)，损失为 2.6-3.5%。 (BeO)-Be-(7) 的同分素 Li-7 的消耗很容易通过氢氧化物沉淀和冲洗来实现。 BeO 和 Al2O3 AMS 目标的质量可以通过使用所谓的“质量因数”进行监控和改进（例如，通过使用更大的离子交换柱），该“质量因数”是稳定核素（Be-6 或 Al-27）的电流，标准化为同批次标准的电流。最后，对于含有低 Cl-nat 浓度和低 Cl-nat 绝对量的大冰样品，离子交换作为 Cl 的预富集工具具有很高的潜力。
A major research focus of the DREsden Accelerator Mass Spectrometry (DREAMS) facility is sample preparation: in-house and at cooperating laboratories. Besides routine applications, developments are mainly driven by the users' demands such as "new" radionuclides (e.g. short-lived Be-7), radionuclides from new matrices or in larger sample amounts and at lower concentrations. Within the chemical preparation of BeO for Be-7,Be-10, Al2O3 for Al-26, AgCl for Cl-36, and Fe2O3 for Fe-60 and actinide AMS targets, we investigated and improved mostly particular steps: For oxide preparation aging for several hours and two-times rinsing of hydroxides is recommended, especially for Be(OH)(2) and Al(OH)(3), to prevent losses in the final preparation steps. Rinsing of freshly precipitated hydroxides can yield to losses as high as 31%. For Al(OH)(3) rinsing with H2O (pH5) instead of pH8-9 is recommended for further reducing redissolving. For Fe-60 and coprecipitated actinides (the latter tested by U6+ and Er3+), rinsing of overnight-aged Fe(OH)(3), yield to 2.6-3.5% losses. The depletion of the isobar Li-7 for (BeO)-Be-(7) is easily gained by hydroxide precipitation and rinsing. The quality of BeO and Al2O3 AMS targets can be monitored and improved (e.g. by using larger ion exchanger columns) by using the so-called "quality factor", which is the current of the stable nuclide (Be-6 or Al-27), normalised to the current of the standard of the same batch. Finally, there is a high potential for ion exchange as a pre-enrichment tool for Cl for large ice samples containing low Cl-nat concentrations and low absolute amounts of Cl-nat.