Performance of a nuclear microprobe to study giant marine aerosol particles

The scanning nuclear microprobe analytical facility of the IRMM was used to determine with PIXE major, minor and trace elements in individual giant marine aerosol particles, collected above the North Sea (particle size > 5 m Ø). The instrumentation is briefly described, and the experimental parameters chosen for these analyses are discussed. Elements with atomic numbers Z > 15 could be determined. Detection limits observed under the prevailing experimental conditions reached down to 50 fg in the case of Ti, V or Cr, corresponding to a mass content of 10 g/g in particles of 15 m size. Quantitative evaluation of the acquired spectra revealed basically three aerosol types in these samples: sea salt particles, sea salt combined with high contents of S, K and Ca, and particles rich in heavier elements (Ti, Cr, Fe, Ni). The agglomeration of several large particles forming a giant one could be visualised directly through the heterogeneity found in the elemental maps of such a particle.