Quantitative Intermethod Comparison of Energy Dispersive X-ray Fluorescence and Atomic Absorption Spectrometry for the Analysis of Urban Dusts and Fly Ash

Abstract

Abstract If environmental analytical chemistry is to be practiced on a routine scale involving a great number of laboratories, certain measures have to be taken to insure the comparability of data; one of these measures is the verification of the results with known materials. In the course of the development of known materials a detailed intermethod comparison of energy dispersive X-ray fluorescence and atomic absorption spectrometry of urban dust samples from three different cities was performed The agreement of results is satisfactory as the discrepancies between the values produced by the two methods are generally below 10% of the content. Some performance characteristics of the two methods are compared. The experiments were designed to give error estimates for the most likely sources of error including the instrumental error of repetitive measurements (AAS and EDXRF), the decomposition (AAS) and fusing (EDXRF) error, the calibration error (AAS) and the error of the bag-house sampling procedure (EDXRF). It is shown that with a live time of 1000 s the instrument precision of EDXRF is generally better than that of AAS and that the bag-house sampling procedure calls for careful blending of the dust before proceeding with the specification of elemental contents. The analytical results are verified with Fly Ash, SRM 1633, from the National Bureau of Standards.