Determination of water-soluble and insoluble compounds in size classified airborne particulate matter

The elemental composition of water soluble and acid soluble size-fractionated airborne particulate matter (APM) was investigated. PM2.5 and PM2.5–10 samples were collected every three days from October 2006 to October 2007 in Buenos Aires, Argentina. The collection was performed on Nucleopore® filters using a GENT sampler. Samples containing fine and coarse particles were subjected to an aqueous leaching to obtain information on the dissolution behaviors of ions, metal and metalloids. Key elements namely, Al, Ba, Ca, Cr, Cu, Fe, Mg, Mn, Pb, Se, Ti and Zn were determined in each fraction by inductively coupled plasma optical emission spectrometry (ICP OES). In the aqueous fractions, Cl−, SO42−, Na+ and NH4+ were determined by high performance liquid chromatography (HPLC). A (6:2:5) mixture of nitric, hydrochloric and perchloric acids was used for leaching metals from the residual filters. For validation of the extraction procedure, the ICP OES measurements the Standard Reference Material NIST 1648 (Urban particulate matter) was subjected to the same analytical procedure that the samples loaded with APM. Total analyte concentration varied from 333.2 μg g− 1 (equivalent to 3.7 ng m− 3) for Ti to 692 mg g− 1 (equivalent to 2.47 μg m− 3) for Ca.