Determination by INAA of trace elements in Fucus sample (IAEA-0140)

Since 1985, our laboratory had the opportunity to check the analytical performance on marine samples using instrumental neutron activation analysis method (INAA), by participating to seven international intercomparison runs organized by the IAEA-Vienna. This paper presents our contribution to the intercomparison exercise on the IAEA-0140 Fucus sp. marine algae. A number of 109 laboratories from 51 countries have participated to this intercomparison run. The brown seaweed Fucus sample, collected on the coast of Normandy (France) was prepared in view of analysis by the Marine Environment Laboratory in Monaco. Concentrations of 25 elements (Al, As, Ba, Br, Ca, Ce, Co, Cr, Cs, Fe, Hf, Hg, K, La, Mg, Mn, Na, Rb, Sb, Sc, Sm, Sr, Th, V and Zn) have been measured by using INAA method. Short and long irradiation were carried out at the WWR-S reactor in Bucharest (neutron fluence rate of 2.5 · 1012n · cm-2 · s-1). Three independent replicate samples were analyzed and the results on a dry weight basis were reported. A very good agreement to the certified concentrations was achieved for Br, Ca, Co, Cr, K, Mn, Na, Sb, Th and V, with values inside of the confidence interval (significance level of 0.05); good results were also obtained for As, Fe, Mg, Rb and Zn. In the case of Hg, our result was higher than the accepted laboratory means; we suppose that a sample contamination occurred. Concerning the information values of the concentrations in the IAEA-0140 Fucus sample, our data for Ce, Cs, Hf, La, Sc and Sm belong to the confidence interval; good results were also obtained for Al and Ba. The IAEA-0140 Fucus marine algae may be used in the future as a Reference Material for the quality control in trace elements analysis of the marine samples. (authors)