SI-TRACEABLE VALUES FOR CADMIUM AND LEAD CONCENTRATION IN THE CANDIDATE REFERENCE MATERIAL, MURST-ISS AL ANTARCTIC SEDIMENT, BY COMBINATIONOF ICP-MS WITH ISOTOPE-DILUTION

The meaning of traceability to SI and how this can be achieved by usin g primary methods is demonstrated in this paper, using the example of the certification for Cd and Pb concentration in the candidate referen ce material, MURST ISS Al Antarctic sediment. The analytical method us ed was inductively coupled plasma mass spectrometry (ICP-MS) in combin ation with isotope dilution (ID). ID is recently recognised as a prima ry method, and its advantages are presented. Microwave pressure digest ion and separation (anion exchange) were applied. The uncertainty budg et calculation is performed according to the EURACHEM and ISO guidelin es, and some useful considerations about other approaches are given.