Metal trace analysis by PIXE and PDMS techniques

Abstract

The risk for the human health due to exposure to aerosols depends on the intake pattern, the mass concentration and the speciation of the elements present in airborne particles. In this work plasma desorption mass spectrometry (PDMS) was used as complementary technique to the particle-induced X-ray emission (PIXE) technique to characterize aerosol samples collected in the environment. The PIXE technique allows the identification of the elements present in the sample and to determine their mass concentrations. The mass spectrometry (PDMS) was used to identify the speciation of these elements present in the samples. The aerosol samples were collected using a 6-stage cascade impactor (CI) in two sites of Rio de Janeiro City. One is an island (Fundão Island) in the Guanabara Bay close to an industrial zone and the other, in Gávea, is a residential zone close to a lagoon and to the seashore. The mass median aerodynamic diameter (MMAD) measured indicated that the airborne particulates were in the fine fraction of the aerosols collected in both locations. In order to identify the contribution of the seawater particles from the Guanabara Bay in the aerosols, seawater samples were also collected at Fundão Island. The samples were analyzed by PIXE and PDMS techniques. The analysis of the results suggests that the aerosols are different in both sampling sites and also exist a contribution from the Guanabara Bay seawater particles to the aerosols collected in the Fundão Island. PIXE allows identification and quantification of the elements heavier than Na ( Z=11) while PDMS allows identification of organic and inorganic compounds present in the samples, as these techniques are used as complementary techniques they provide important information about the aerosols characterization.