Comparison of extracting solutions for elemental fractionation in airborne particulate matter

It is here described the comparison of extraction efficiency of some solutions (acetate buffer, deionized water, diluted HNO3 and EDTA) frequently adopted in literature for evaluating the elemental solubility in airborne particulate matter. This comparison was performed considering the distribution of As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Na, Ni, Pb. S, Si, Sb, Sn, Sr, Ti, V. Zn between the extractable and mineralized residual fractions on the NIST 1648 certified material, PM10 real samples and size-segregated samples, collected by a 13-stage impactor. The extracting solutions were evaluated by comparing extractive efficiencies and robustness towards some factors, such as acidity and concentration of complexing species, that have great environmental variability and that could be able to modify the extractive efficiency. Furthermore, extraction methods application to size-segregated samples allowed estimating the selectivity of extracting solutions towards dimensionally characterized emission sources, as dusts originated from abrasion and road dust re-suspension. On the basis of the obtained results, it was possible to define the main advantages and disadvantages resulting from the use of different extracting solutions, necessary to make possible the comparison of environmental studies carried out in different extractive conditions and to start up a proper study for harmonizing extracting procedures. (C) 2010 Elsevier B.V. All rights reserved.