SI-traceable values for cadmium and lead concentration in the candidate reference material, MURST-ISS A1 Antarctic sediment, by combination of ICP-MS with isotope dilution

The meaning of traceability to SI and how this can be achieved by using primary methods is demonstrated in this paper, using the example of the certification for Cd and Pb concentration in the candidate reference material, MURST ISS A1 Antarctic sediment. The analytical method used was inductively coupled plasma mass spectrometry (ICP-MS) in combination with isotope dilution (ID). ID is recently recognised as a primary method, and its advantages are presented. Microwave pressure digestion and separation (anion exchange) were applied. The uncertainty budget calculation is performed according to the EURACHEM and ISO guidelines, and some useful considerations about other approaches are given.