Does Filtration Efficiency Affect Measurements of Particle Chemical Composition?

Abstract

A direct method to measure filtration efficiency was developed and used for the determination of the efficiency of a Nuclepore filter. This needs two equivalent filtration systems operated in sequence. The amount of particulate matter collected on each system is measured and introduced in a simple formula. The particulate masses deposited on the filters in each system were measured as total mass, by balance gravimetry, and as individual elemental masses, by PIXE (particle induced X-ray emission). With this very general method it was possible to determine the efficiencies of a 0.4 μm Nuclepore filter operated with a stacked filter unit for particles less than 2.5 μm in total mass and elemental masses. The experiment showed that the efficiency of this filter is very poor for some specific elements, like sulfur, that are concentrated in very small particles.