MICROWAVE-ASSISTED VAPOR-PHASE ACID DIGESTION OF CELLULOSE NITRATE FILTERS FOR ELEMENTAL ANALYSIS OF AIRBORNE DUST SAMPLES

A microwave-assisted vapor-phase digestion procedure was developed for microanalytical investigation of airborne dust samples collected on c ellulose nitrate filters. The decomposition of a filter placed in a qu artz microvial was carried out by oxidation using a mixture of HNO3 an d H2O2 in a closed Teflon bomb. To avoid charring of the filter the te mperature was increased from 25 to 180 degrees C in Eve steps over 97 min. The decomposition rate of cellulose nitrate amounted to 95%. Reco very of Ni, V, Pb, Pt, and Pd ranged from 85 to 94%. The applicability of this sample preparation procedure resulting in 1 ml solution was d emonstrated by investigation of airborne dust samples collected in the Clark tunnel in Budapest using total reflection X-ray fluorescence sp ectrometry. (C) 1998 Academic Press.