Development of Mercury Analysis by NanoSIMS for the Localization of Mercury–Selenium Particles in Whale Liver

Abstract

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 (ΔM/M ≥ 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 (Physeter macrocephalus). This demonstrated the applicability of NanoSIMS not only for mercury detection in surface analysis but also for mercury mapping in biological samples.

Quantitative mapping of mercury and selenium in mushroom fruit bodies with laser ablation–inductively coupled plasma-mass spectrometry

“…When it comes to other biological matrices than fungi, the number of publications on spatially resolved measurements of Hg and/or Se is somewhat higher, and different techniques have been employed for this purpose, including LA-ICP-MS, X-ray spectroscopic techniques like (synchrotron-based, micro-) XRF [15], (nanoscale) secondary ion mass spectrometry (SIMS) [16], and laser-induced breakdown spectroscopy (LIBS) [17]. From these approaches, LA-ICP-MS offers excellent limits of detection (LODs, down to the ng g −1 -low pg g −1 level, depending on the element and ablation parameters), multi-elemental capabilities, a relatively simple sample preparation, comparatively good robustness against matrix effects, and a wide linear dynamic range [18][19][20].…”

NanoSIMS as an analytical tool for measuring oxygen and hydrogen isotopes in clay minerals from palaeosols: Analytical procedure and preliminary results

“…NanoSIMS (nanoscale secondary ion mass spectrometry) is a dynamic SIMS technique that allows the mapping of different chemical elements at nanometre scale, with high sensitivity as well as high spatial resolution (Mosenfelder et al, 2011;Blanc et al, 2012;Subirana et al, 2021).…”

“…The focus of the primary ion beam perpendicular to the sample surface allows the high spatial resolution achieved by NanoSIMS, combining with high-sensitive chemical and isotopic images (Subirana et al, 2021). The primary ion bean of NanoSIMS can be positive (Cs + ) or negative (O -), in order to generate respectively either negative or positive secondary ions from the sample surface and obtain the corresponding elemental images.…”

“…plasma Oion beam allows high lateral resolution imaging below 40 nm of electropositive elements, such as most metals (Malherbe et al, 2016;Agüi-Gonzalez et al, 2019;Subirana et al, 2021). In addition, the NanoSIMS instrument is equipped with a charged-coupled device (CCD) camera, which allows optical imaging and thus the preselection of regions of the sample of interest for subsequent SIMS analysis (Chew et al, 2014;Ender et al, 2019).…”

High-speed mapping of Hg and Se in biological tissue via laser ablation-inductively coupled plasma-mass spectrometry

“…detoxication of Hg by Se) is addressed in many papers. 18,[26][27][28][29] To obtain high-quality Hg and/or Se maps with sequential scanning-type ICP-mass spectrometers, all instrument settings and data acquisition conditions have to be carefully selected and/or synchronized to accommodate for these longer SPR durations, which has several important consequences. Obviously, a long SPR duration will reduce the pixel acquisition rate and thus increase measurement time and reduce sample throughput, but it will also negatively affect the S/N ratio, which in turn may require an increase in beam diameter as compensation, deteriorating the spatial resolution of the elemental map.…”