An estuary water reference material, LGC 6016, for the determination of trace levels of Cd, Cu, Ni, Pb and Zn was certified by isotope dilution ICP-MS. Pb and Cd were determined using a conventional quadrupole ICP-MS. Cu, Zn and Ni were determined using a magnetic sector ICP-MS which allowed significant polyatomic interferences to be overcome. The certified values were 186 ng/g Ni, 190 ng/g Cu, 75 ng/g Zn, 101 ng/g Cd and 196 ng/g Pb. The combined uncertainty was 2-3% for each element. Certification by conventional interlaboratory analysis was unsatisfactory for this reference material due to the large discrepancies in the reported concentrations.
J-Environ-Monit. Oct 2001; 3(5) 469-474