School of Engineering and Science - Jacobs University

1.50 SGR-1b (n=3)
1.25
JUB / reference average
1.00
0.75
0.50
0.25
0.00
Sc Ti Co Ni Rb Sr Y Zr Nb Mo Cs Ba La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Hf Ta W Pb Th U
Figure 17. Accuracy estimation for ICPMS analysis of shale SGR-1b, where n equals the number of
separate HF-HClO 4 sample decompositions and ICPMS analyses in 0.5 M HCl. Grey bars represent
variability in the calculated ratio that is due solely to uncertainty in the reference average. Vertical lines
represent the variability in the calculated ratio due to the uncertainty of the JUB data, and all data are
presented in App. 1. The measured concentrations for Ni, Y, Tb, and Tm are not necessarily considered
anomalous, and likely represent small interferences (Ni) and relatively large uncertainties in the
reference data (Y, Tb, Tm; see text and App. 1).
not likely to adversely affect Nb determinations, assuming Nb is present in the sample
at concentrations of several mg/kg or higher.
SGR-1b
The SGR-1b (Green River) shale is a petroleum and carbonate rich CRM
issued by the USGS. The SGR-1b shale is identical to the original SGR-1 shale (S.A.
Wilson, USGS, personal communication) and contains 6.5% Al 2 O 3 , 4.4% MgO, 8.4%
CaO, 3.0% Fe 2 O 3 , and minor amounts of Mn (267 mg/kg). While the Al content of
SGR-1b is low compared to the SCo-1 shale, it is still high enough to produce
significant Al-chloride interferences on 62 Ni. As a result Ni concentration data
reported for SGR-1b are determined solely from analyses of the 60 Ni isotope. For the
remaining major elements, significantly higher MgO and CaO in SGR-1b compared
to SCo-1 would be expected to erroneously increase measured signal intensities for
60 Ni, due to MgCl and CaO(H) inteferences. The combined magnitude of these Mg
and Ca interferences on 60 Ni is estimated to be ~2 mg/kg (App. 2), and this is
41