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

• Main Authors: Maria Angels Subirana (11413770), Lhiam Paton (11413773), James Hall (2176208), Andrew Brownlow (408477), Eva M. Krupp (1263984), Jörg Feldmann (1263990), Dirk Schaumlöffel (1956622)
• Format: Other Non-Article Part of Journal/Newspaper
• Language: unknown
• Published: 2021
• Subjects: Biophysics; Biochemistry; Cell Biology; Ecology; Developmental Biology; Inorganic Chemistry; Biological Sciences not elsewhere classified; Chemical Sciences not elsewhere classified; Physical Sciences not elsewhere classified; ≥ 3200 ); sup >–</ sup; sup >+</ sup; strong matrix effect; physeter macrocephalus ); new rf plasma; natural isotopic abundances; nanometer scale combined; isotopic pattern corresponded; challenging issue due; newly developed method; high mass resolution; hgse particles accumulated; mercury isotopes could; secondary ion yield; dynamic sims technique; ion source; high sensitivity; hgse nanocrystals; developed applying; mercury analysis; surface analysis; successfully applied; sperm whale; secondary ions; polyatomic interferences; liver tissue; higher sensitivity; first time; electropositive elements; chemical imaging; chemical elements; biological samples; Physeter macrocephalus; Sperm whale
• Online Access: https://doi.org/10.1021/acs.analchem.1c02769.s001

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 M / 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.