X-RAY SPECTROMETRY X-Ray Spectrom. 2005; 34: 411–416 Published online 17 June 2005 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/xrs.844 Accumulation of elements in annual tree rings measured by synchrotron x-ray fluorescence analysis † A. E. S. Vives, 1∗ R. M. C. Silva, 2 J. G. da S. Medeiros, 3 M. Tomazello Filho, 3 R. C. Barroso, 4 O. L. A. D Zucchi 5 and S. Moreira 6 1 Universidade Metodista de Piracicaba, Santa Barbara D’Oeste, SP, Brazil 2 Centro de Energia Nuclear na Agricultura, Piracicaba, SP, Brazil 3 Escola Superior de Agricultura ‘Luiz de Queiroz’, Piracicaba, SP, Brazil 4 Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil 5 Universidade de S ˜ ao Paulo, Ribeir ˜ ao Preto, Ribeir ˜ ao Preto, SP, Brazil 6 Universidade Estadual de Campinas, Campinas, SP, Brazil Received 14 July 2004; Accepted 3 March 2005 Wood samples of hardwood (Eucalyptus sp.) and softwood (Pinus sp.) showing typical anatomical features treated with CCA (copper–chromium–arsenic) were analyzed. The distribution and quantification of metals in the sapwood/heartwood (Eucalyptus sp.) and in the growth-rings (Pinus sp.) were obtained. The samples were scanned in 320 μm steps in the vertical direction. An x-ray beam of ∼320 × 180 μm was used. For excitation of the elements white beam synchrotron radiation was employed and for x-ray detection an Si(Li) semiconductor detector. The x-ray fluorescence intensities for the elements K, Ca, Cr, Mn, Cu, Zn and As were measured. Heterogeneous distribution of the elements was verified across growth-rings indicating irregular efficiency of the preservative distribution inside wood in the softwood samples. As expected, in eucalyptus the presence of the elements Cr, Cu and As was verified in the sapwood region only. Copyright  2005 John Wiley & Sons, Ltd. INTRODUCTION The possibility of determining the concentration of mineral elements in annual tree rings is important in wood chemistry, protection and environmental science. X-ray fluorescence analysis allows one to determine the mineral contents within and between tree rings 1 and also to understand their distribution in wood treated with preservatives. 2,3 The elements Cu, Cr and As are commonly used to protect wood against fungal degradation and insect attack and to extend its life service when exposed to environmental conditions. 3 The efficiency and durability of preserved wood is influenced by several factors, such as salt concentration, fixation and internal distribution throughout the internal wood cells, related to the anatomical features of the species. 4 The objective of this study was to employ synchrotron x- ray fluorescence (XRF) analysis for the evaluation of the accumulation of natural elements and minerals used as preservative components in softwoods (Pinus sp.) and hard- woods (Eucalyptus sp.). L Correspondence to: A. E. S. Vives, Universidade Metodista de Piracicaba, UNIMEP/FEAU, Rodavia Santa B´ arbara D’Oeste, Iracenn´ apolis, CEP 13450-000 Sant´ a B´ arbara D’Oeste, SP, Brazil. E-mail: aevives@unimep.br † Presented at the First European Conference on X-ray Spectrometry, EXRS 2004, Alghero, Sardinia, 6–11 June 2004. Contract/grant sponsor: Brazilian Synchrotron Light Source (LNLS); Contract/grant number: D09B-XRF-1535. Contract/grant sponsor: Research Fund of the Methodist University of Piracicaba, UNIMEP/FAP. EXPERIMENTAL Preparation and measurement of samples Wood samples of hardwood (Eucalyptus sp.) and softwood (Pinus sp.) treated with CCA (CrO 3 –CuO–As 2 O 5 ) by the vacuum-pressure method 1 were used. The Laboratory of Wood Preservatives of the Technological Research Institute (IPT), S˜ ao Paulo State, supplied these samples. Wood cross- sections 1 mm thick were cut from discs of Pinus sp. (named P1 and P2, samples of 10 cm length) and Eucalyptus sp. (named E, samples of 4 cm length). Within radial wood samples, the sapwood–heartwood regions of Eucalyptus sp. and the second (15–30 mm), fifth (50–65 mm) and seventh (75–90 mm) annual tree rings of Pinus sp. were selected to determine the mineral contents (Fig. 1). The experiments were carried out in the XRF station of the XRF beamline installed at the Brazilian Synchrotron Light Laboratory (LNLS), Campinas. The electron energy inside the storage ring is 1.37 GeV with a dipole magnetic field of 1.65 T, which produces a critical photon energy of 2.08 keV. The synchrotron radiation source for the XRF beamline is the D09B (15 ° ) bending magnet of the storage ring. 5 All measurements were performed under normal condi- tions of pressure and temperature. The standard excitation geometry (45 ° –45 ° ) was used and the wood samples were excited with a white beam collimated to produce a beam size of 320 ð 180 μm. The fluorescence spectrum was recorded with an Si(Li) detector of 165 eV FWHM at 5.9 keV. The wood samples were scanned in 320 steps μm in the radial direction with a counting time for each step of 60 s. All the spectra Copyright  2005 John Wiley & Sons, Ltd.