Hello Hyam:

Microwave acid digestión and then an elemental analysis by ICP has good results, even if the colected mass is small. You can use EPA Method:

http://www.epa.gov/ttnamti1/files/ambient/inorganic/mthd-3-4.pdf

We noticed reduction of sulfate by the foil during long-term digestion:

Atmospheric Environment 12/1997; 31(23):3955-3962; sorry, I do not have an electronic copy

Can you change the collection media or aluminum foil is mandatory for your application? For polycarbonate filters, I have experience with scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) for the morphology and elemental composition. Ionic cromatography also works fine for the major ions.

i totally agree with  Sandra Mogo but i thinke Berner impactor  collection media is aliminuim foil how she can change it? do u have any expert about preparation of polycarbonate filters for this type of inpactor? collection plat as a ring with hole diamitar as 2 cm nearly ?

Sandra

IC can be done using with Al foils

SEM/EDX is not a quantitative analysis method and how do you handle a rather thick and non-uniform deposit in your analysis?

Was it collected in bulk or as dispersed particles on Al-foil (short time collection)? what you want to do: bulk quantification or single particle characterization?

As stated above by Harry, SEM-EDX can be applied directly on these samples : but preferably for semiquantitative single particle analysis....assigning approx. chemical composition and morphology based on EPMA [many softwares perform semiquantitative analysis of individual particles: C.-U. Ro, J. Osan, I. Szaloki, K.-Y. Oh, H. Kim, R. Van Grieken. "Determination of Chemical Species in Individual Aerosol Particles Using Ultra-thin Window EPMA", Environmental Science & Technology, 34, 3023-3030 (2000)--highlighted in Analytical Currents of Analytical Chemistry journal: Analytical Chemistry, 72, 576A, (2000)). DOI:10.1021/es9910661)] and SEI images.

If you have bulk and uniform thin layer deposit on the Al-foils, you can go for non-destructive XRF (preferably EDXRF) for bulk elemental quantification without digesting the samples. You may have interference and secondary excitation from the Al foil...but they can be corrected or background corrections can be done....However for bulk analysis in XRF also PTFE/cellulose filter media are better

Or apply IC as Harry states above.

If you do not want to destroy your samples, XRF is most recommended, as well as Particle Induced X-ray Emission (PIXE). As explained by D. Gupta, corrections for the filter itself can be done. EPMA may not be very useful, because it focuses mostly on single particle analysis and often the electron beam penetration is smaller than particle size. This is not the case for XRF or PIXE.

However, for PIXE it is much better to use polycarbonate filters.

IC or ICP are destructive techniques. IC is limited to only a few ions.

The most preferable technique for elemental analysis on aluminum impactor stages for aerosols is X-ray Fluorescence (XRF) spectroscopy.