Determination of the REE in geological reference materials DTS-1 (dunite) and PCC-1 (Peridotite) by ultrasonic and microconcentric desolvating nebulisation ICP-MS

Inductively coupled plasma-mass spectrometry is well suited for the precise , accurate and rapid determination of rare earth elements in most geologica l samples. However, determination of rare earth elements in certain mantle- derived materials, without applying preconcentration techniques, remains pr oblematical due to low natural concentrations (generally < 1 ng g(-1)). Con sequently, USGS reference materials DTS-1 (a dunite) and PCC-1 (a partially serpentinized harzburgite) have only suggested rather than recommended val ues for the rare earth elements in reference material compilations. We comp ared results obtained using two ICP-MS instruments: a U-5000AT ultrasonic n ebuliser coupled to a PQ2+ quadrupole ICP-MS and an ELEMENT sector field IC P-MS equipped with a MCN-6000 microconcentric desolvating nebuliser, with t he suggested literature values for these two reference materials. Precision and accuracy of analytical methods employed by both instruments were demon strated by excellent relative standard deviations (< +/- 2%) and interlabor atory agreement (< +/- 5%) for numerous analyses of BHVO-1 and BIR-1, which are well established with rare earth elements contents at the mu g g(-1) l evel. Repeat analyses of DTS-1 and PCC-1 at each laboratory indicate that e ach method is generally precise to better than +/- 5% at sub-mu g g(-1) lev els. Furthermore, values from both instruments generally agree to within +/ - 10%. Our DTS-1 and PCC-1 values agree reasonably well with selected data reported in the literature (except for Ce and Sm in DTS-1) but exhibit poor er agreement with reported compilation values. With the demonstrated level of precision and accuracy, we contend that these new values for DTS-1 and P CC-1, generated by two different instruments, are the best estimates of the true whole-rock composition of these samples reported to date.