The third step involved adding 50.0 μL of internal standard, which
contained 6
Li, 45Sc, 72Ge, 89Y, 115In, 159Tb and 209Bi, to cover a reasonable
mass range. Then 0.95 mL of 10.5% HNO3 was added to dilute the sample
to its final volume of 5.0 mL. The 10 ppb spiked samples were prepared
by adding 50.0 μL of internal standard, 5.0 μL of a 10 ppm standard cal-
ibration mixture, and 0.945 mL of 10.5% HNO3. Once all of the analysis
vials were diluted, the samples were run with the ICP–MS/MS. All in-
strumental parameters are depicted in Supplemental Table T-1.