ANALYSIS OF TRACE-ELEMENTS IN TRUNK WOOD BY THICK-TARGET PIXE USING DRY ASHING FOR PRECONCENTRATION

Thick-target Particle Induced X-ray Emission (TTPIXE) was used for the quantitative determination of trace-element concentrations in trunk w ood. The wood samples were preconcentrated by dry ashing to improve th e reliability of the sampling and the sensitivity of the analytical me thod. Samples of Scots pine (Pinus sylvestris) and Norway spruce (Pice a abies) were collected from a polluted area (Harjavalta) as well as f rom a relatively nonpolluted area (Merimasku) in southwestern Finland. The elements studied were P, S, K, Ca, Mn, Fe, Ni, Cu, Pb, Rb, Sr, Ba , Cd and Ag. TTPIXE combined with dry ashing is a sensitive and reliab le analytical technique for most elements studied. The method was vali dified by using several certified reference materials and also by ICP- MS analysis. Due to the low ash content (0.2-0.4%) in wood a high prec oncentration factor can be obtained. Differences in trace-element upta ke were observed between the two tree species studied. Trunk wood from the polluted area contained higher concentrations of heavy metal ions .