Quality assurance in elemental analysis of airborne particles

摘要

Instrumental neutron activation analysis (INAA) and particle induced X-ray emission (PIXE) are commonly used to yield multielemental data in atmospheric studies. In this work the quality assurance of the analytical data is discussed based on two studies. The first is a precision study, involving sampling and analysis of air particulate matter in the size ranges of the aerodynamic diameter (AD) <2.5 μm and 2.5 μm < AD < 10 μm, using two Gent collectors, operating side-by-side, on a daily basis. Mass concentrations obtained by gravimetry, for the two collectors, were compared showing a very good reproducibility. Elemental analysis was carried out in different parts of the same filter, testing both the homogeneity of the aerosol sample and the precision of the techniques. A relation between the elemental concentration and the differences obtained for different parts of the same filter was observed. Results suggest that, for the elements studied, data are reproducible to within 5―15%. In the second INAA and PIXE analysis of different sections of the same filter are discussed. Results indicate a good agreement for the determination of K, Fe and Zn by the two techniques.