Precise and Accurate Doping of Nanoporous Silica Gel for the Synthesis of Trace Element Microanalytical Reference Materials
Precise and Accurate Doping of Nanoporous Silica Gel for the Synthesis of Trace Element Microanalytical Reference Materials
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纳米多孔硅胶精密掺杂用于合成微量元素分析标准物质
DOI：
10.1111/ggr.12120
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发表时间：
2016
影响因子：
3.8
通讯作者：
W. O. Nachlas
中科院分区：
文献类型：
--
作者：
W. O. Nachlas
本研究提出了一种实验程序，以制造含有特定质量分数的选定元素的高纯石英玻璃。该程序用于制备掺杂有微量质量分数Ti的玻璃，目的是在测量石英中的微量元素时提高分析置信度。进行了系统的测试，以确定掺杂纳米多孔硅胶的理想条件和程序，具有最高的掺杂剂回收效率。将硅胶在浓HCl中清洗，浸入控制pH值的非极性掺杂介质中，并掺杂精确量的ICP-MS标准品溶液。使用由较长链分子组成的液体作为掺杂介质减少了回收，这表明大分子可以阻塞纳米孔以抑制掺杂剂的毛细吸收。使用结晶石英的对照实验增强了纳米多孔硅胶用于以痕量级精度掺杂的有效性。热压掺杂有不同Ti质量分数的硅胶的层状聚集体以产生多层参考材料，其在各种空间尺度下用多种技术进行分析。颗粒内尺度分析（阴极发光扫描电子显微镜，电子探针显微分析），在单颗粒尺度（西姆斯），在样品层尺度（电子探针，激光消融-ICP-MS）和批量（ICP-OES）在大多数微量分析技术的样品体积特征下证明了可接受的均匀性，并表明纳米多孔硅胶有希望作为用于制备参比材料的高保留掺杂基底，激光、电子和离子束显微分析。
This study presents an experimental procedure to fabricate high‐purity silica glass containing a selected element at a specified mass fraction. The procedure was used to prepare glasses doped with trace‐level mass fractions of Ti with the goal of improving analytical confidence when measuring trace elements in quartz. Systematic tests were performed to determine the ideal conditions and procedures for doping nanoporous silica gel with the highest efficiency of dopant recovery. Silica gel was cleaned in concentrated HCl, immersed in a non‐polar doping medium at a controlled pH and doped with precise quantities of ICP‐MS standard solution. Using liquids composed of longer chain molecules as the doping medium diminishes recovery, suggesting that large molecules could obstruct nanopores to inhibit capillary uptake of the dopant. A control experiment using crystalline quartz reinforced the effectiveness of nanoporous silica gel for doping with trace‐level precision. Layered aggregates of silica gel doped with different Ti mass fractions were hot‐pressed to create multi‐layered reference materials that were analysed with multiple techniques at a variety of spatial scales. Analyses at the intra‐grain scale (cathodoluminescence scanning electron microscopy, electron probe microanalysis), at the single grain scale (SIMS), at the sample layer scale (EPMA, laser ablation‐ICP‐MS) and at the bulk scale (ICP‐OES) demonstrated acceptable homogeneity at sample volumes characteristic of most microanalysis techniques and show that nanoporous silica gel holds promise as a highly retentive doping substrate for preparing reference materials for laser‐, electron‐ and ion‐beam microanalysis.