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 cellulose nitrate filters. The decomposition of a filter placed in a quartz microvial was carried out by oxidation using a mixture of HNO(3) and H(2)O(2) in a closed Teflon bomb. To avoid charring of the filter the temperature was increased from 25 to 180 degrees C in Eve steps over 97 min. The decomposition rate of cellulose nitrate amounted to 95%. Recovery 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 demonstrated by investigation of airborne dust samples collected in the Clark tunnel in Budapest using total reflection X-ray fluorescence spectrometry. (C) 1998 Academic Press.