CNRS, Université de Pau et des Pays de l'Adour, E2S UPPA, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux, UMR 5254, 64000 Pau, France.
TESLA-Analytical Chemistry, Institute of Chemistry, University of Graz, 8010 Graz, Austria.
Anal Chem. 2021 Sep 21;93(37):12733-12739. doi: 10.1021/acs.analchem.1c02769. Epub 2021 Sep 9.
Nanoscale secondary ion mass spectrometry (NanoSIMS) is a dynamic SIMS technique, which offers high spatial resolution allowing the mapping of chemical elements at the nanometer scale combined with high sensitivity. However, SIMS for mercury analysis is a challenging issue due to the low secondary ion yield and has never been done on NanoSIMS. The introduction of an rf plasma oxygen primary ion source on NanoSIMS enabled higher lateral resolution and higher sensitivity for electropositive elements such as most metals. In this paper, for the first time, mercury analysis by NanoSIMS was developed applying the new rf plasma O ion source. All mercury isotopes could be detected as Hg secondary ions and the isotopic pattern corresponded to their natural isotopic abundances. Furthermore, Hg detection in HgSe nanocrystals has been investigated where polyatomic interferences from selenium clusters were identified and separated by high mass resolution (Δ/ ≥ 3200). However, in the presence of selenium a strong matrix effect was observed, decreasing the Hg secondary ion yield. In addition, a detection of Se ions was possible, too. The newly developed method was successfully applied to nanoscale localization by chemical imaging of HgSe particles accumulated in the liver tissue of sperm whale (). This demonstrated the applicability of NanoSIMS not only for mercury detection in surface analysis but also for mercury mapping in biological samples.
纳米二次离子质谱 (NanoSIMS) 是一种动态 SIMS 技术，具有高空间分辨率，可结合高灵敏度对纳米级化学元素进行映射。然而，由于二次离子产率低，汞的 SIMS 分析一直是一个具有挑战性的问题，并且从未在 NanoSIMS 上进行过。在 NanoSIMS 上引入射频等离子体氧初级离子源，使大多数金属等正电性元素具有更高的横向分辨率和更高的灵敏度。本文首次应用新型射频等离子体 O 离子源开发了 NanoSIMS 对汞的分析。所有汞同位素都可以作为 Hg 二次离子被检测到，其同位素模式与它们的天然同位素丰度相对应。此外，还研究了 HgSe 纳米晶体中的 Hg 检测，其中硒簇的多原子干扰通过高质量分辨率（Δ/ ≥ 3200）被识别和分离。然而，在硒的存在下，观察到强烈的基质效应，降低了 Hg 二次离子的产率。此外，也可以检测到 Se 离子。新开发的方法成功地应用于通过化学成像对在抹香鲸肝脏组织中积累的 HgSe 颗粒进行纳米尺度定位（）。这证明了 NanoSIMS 不仅可用于表面分析中的汞检测，也可用于生物样品中的汞测绘。
