Analytical Sciences

Development and Characterization of a Portable Total Reflection X-ray Fluorescence System Using a Waveguide for Trace Elements Analysis

Ana Cristina M. da COSTA,* Ubiratan B. de ARAÚJO,* Edgar F. O. de JESUS,* Marcelino J. ANJOS,** and Ricardo T. LOPES*

*Nuclear Instrumentation Laboratory-COPPE/UFRJ, P. O. Box: 68509, 21941-972 Rio de Janeiro, Brazil
**State University of Rio de Janeiro, Physics Institute, 20550-013 Rio de Janeiro, Brazil

This paper presents a portable total reflection X-ray fluorescence system composed of a 15 W X-ray tube, with a gold anode, a waveguide constituted by two Perspex^® parallel plates, a Si PIN detector and a quartz optical flat. The critical angle of the total reflection system was experimentally determined by measuring a zinc solution (100 mg/L). The accuracy of the system was checked using SRM 1577b Bovine Liver by NIST as standard reference material. We obtained the absolute detection limits of the following elements: P (450 ± 40 ng), S (200 ± 31 ng), K (30 ± 2.5 ng), Ca (19 ± 3.5 ng), Mn (4.1 ± 0.5 ng), Fe (3.6 ± 0.9 ng), Cu (3.3 ± 0.4 ng) and Zn (3.5 ± 0.3 ng). This paper shows that it is possible to produce total reflection X-ray fluorescence with very compact, efficient, low-cost and easy-to-handle instrumentation using a low-power X-ray tube and a Si PIN compact detector.

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