INTERLABORATORY COMPARISON OF MASS-SPECTROMETRIC METHODS FOR LEAD ISOTOPES AND TRACE-ELEMENTS IN NIST SRM-1400 BONE ASH

The results of an interlaboratory comparison are reported for the lead isotope composition and for trace element concentrations in NIST SRM 1400 Bone Ash obtained using quadrupole and magnetic-sector inductivel y coupled plasma mass spectrometry (ICP-MS) and (for the Pb isotopes o nly) thermal ionization mass spectrometry (TIMS). Concentrations of 42 analytes, in addition to the 17 listed by NIST, are presented, includ ing the rare earth elements. Twenty-six of these analytes are consider ed to have been reliably determined based upon the agreement of two or more laboratories, or based upon data from a single laboratory with c onsideration of the potential interferences. Nickel and cobalt were re liably determined only by medium-resolution magnetic-sector ICP-MS, or by quadrupole ICP-MS following matrix separation with an ion-exchange column. The Pb isotope composition reported here from TIMS agrees wit hin 0.09% relative with previously reported, non-certified values for this standard reference material. The atomic abundances of Pb-208, Pb- 207 and Pb-206 determined by ICP-MS are statistically equivalent to th e best-estimate TIMS values or differ statistically by 0.17% at most, The information provided in this paper will enhance the utility of thi s reference material.