Self Absorption Corrections for X-Ray Fluorescence Analysis of Aerosols

Abstract

A procedure is described for making self absorption corrections for x-ray fluorescence analysis of ambient air aerosols which are collected in two size ranges with a dichotomous sampler. Calculations for fine particles are based on the assumption of a uniform layer of accumulated deposit which has an exponentially decreasing depth profile within a membrane filter. Coarse particles are treated as spheres with a log normal mass distribution which is subject to modification by the sampling device. An average attenuation and the associated uncertainty is deduced for coarse particles by considering a wide variety of possible chemical compositions.

Direct determination of metallic elements in solid, powder samples with electrically vaporized thin film atomic emission spectrometry

“…Activation methods, microprobe techniques, and mass spectrometry all require expensive apparatus, and frequently sample handling is complex and time-consuming. X-ray fluorescence has only moderate sensitivity and, in addition, exhibits significant matrix and particle-size effects (4,5). While furnace techniques with atomic spectrometry have met with some success (6), significant concomitant effects are not infrequent.…”

“…The first theoretically derived expressions to account for primary and secondary absorption for right-angle geometry appeared in 1938 (5). They were found to be simplistic and failed to include the possibility of absorbing species other than the single fluorophore.…”

Particle size and composition effects in x-ray fluorescence analysis of pollution samples

“…Data interpretation is much more troublesome if particles shield each other, or if particles penetrate into a coarse substrate and are partially shielded by it. Some of the problems with such samples have been discussed elsewhere (4)(5)(6).…”