REFERENCE MATERIALS FOR QUALITY ASSURANCE IN SEA-WATER ANALYSIS - PERFORMANCE OF TOTAL-REFLECTION X-RAY-FLUORESCENCE IN THE INTERCOMPARISON AND CERTIFICATION STAGES

The certification of a sea-water reference material (CRM 403) was completed by the Community Bureau of Reference (BCR) of the Commission of the European Communities during an intercomparison exercise in which we were participants along with other highly experienced laboratories, who, beforehand, had given evidence of outstanding performance. Further, we participated in a feasibility study on estuarine water. In both studies we used total-reflection X-ray fluorescence analysis (TXRF) for the determination of V, Mn, Fe, Co, Ni, Cu, Zn, Pb and U on the nmol/kg level. The enrichment of the trace metals and the separation from the salt matrix were performed by complexation with sodium dibenzyldithiocarbamate and reverse-phase chromatography. In this paper, the high performance of our TXRF results is compared to other analytical techniques like voltammetric and atomic absorption methods.