Chemical analyses after consecutive extraction of inorganic components in suspended particulate matter in Bilbao (Spain)

An extraction procedure for determining the most important inorganic components in urban suspended particulate matter collected in glass fiber filters has been used by treating the whole sample, rather than treating one filter portion for each analysis. Certain blank filters have been treated following the proposed extraction procedure in order to ascertain the leaching problems derived from the use of glass fiber filters for collecting the samples. In the acid extractable fraction, the main problem was that high amounts of Zn were leached from the filters themselves which rendered impossible measurements of this metal in the samples. Many of the water soluble components rendered high values in the blank filter treatment, especially SO42-, Cl-, Ca2+ and Na+. Consequently, the sample measurements have been carried out using, as blank reference, the external crowns of the filters used for collecting the samples. The extraction procedure has been validated by using one certified material.