Application of SIMS to the analysis of environmental samples

As an example of surface analysis of environmental samples, SIMS was applied to airborne particulates, fish otoliths (a calcareous ear-stone) and biotites (a rock-forming aluminosilicate mineral). Airborne particulates deposited on leaf surface were analyzed directly by fast atom bombardment (FAB)-SIMS using an O2 primary neutral beam. Some metal elements, such as Pb, of aerosol origin could be detected. Local areas of a thin section of an otolith were analyzed by FAB-SIMS. Line scans and images of secondary ions revealed seasonal periodicity in Sr, Na and K concentrations in the otolith that corresponded to the annual band structure. Surface alteration of acid-treated and naturally weathered biotites was studied by SIMS depth profiling using an O- primary ion. The depth profile of the acid-treated biotite showed the formation of an altered surface layer rich in Si. In contrast a thick altered surface layer was not observed and Al was held on the surface under natural weathering