High-energy polarized-beam EDXRF for trace metal analysis of vegetation samples in environmental studies

摘要

The aim of this work was to achieve improved instrumental sensitivity and detection limits for the determination of several trace elements (Cd, Pb, As, Cu, Fe and Zn) in different vegetation species collected at two mining areas in Spain (Aran Valley and Cartagena) by using new instrumentation based on high-energy polarized-beam energy-dispersive x-ray fluorescence analysis. Cd was determined by using its Ka line, while the mutual interference of As and Pb was solved by employing selective excitation conditions with targets of different materials. The use of a standardless fundamental parameter approach (IAEA QXAS) allowed the determination of other metals in the absence of suitable certified reference materials and to compensate accurately for self-attenuation effects in the sample. The proposed methodology provides an alternative analytical tool to classical destructive analytical methods, commonly applied for the determination of these toxic elements in vegetation matrices, with accuracy and precision levels fulfilling the requirements for environmental studies. Copyright (c) 2006 John Wiley & Sons, Ltd.