Extended data Figure 3. Ruthenium isotope data obtained for ng ml^-1 Alfa Aesar Ru standard solutions doped with variable amounts of Ni and S.

The effect of Ni argide interferences on the measured ε¹⁰⁰Ru (a) and ε⁹⁸Ru (b) isotopic compositions of a 100 ng ml^-1 Ru standard solution doped with varying amounts of Ni. The accuracy of the measured isotopic compositions is not affected for samples with Ni/Ru < 10^-2. Panels (c) and (d) show that even if high amounts of S (S/Ru = 5) are present in the analyzed sample solutions, this has no effect on the accuracy of the measured ε¹⁰⁰Ru and ε⁹⁶Ru data. Vertical dashed lines in (c) and (d) indicate the range of S/Ru of the analyzed samples. The blue areas in (a-d) indicate the external reproducibility of the method as defined by the standard deviation (2 s.d.) of replicate digestions and repeated analysis of the UG-2 reference sample (see Methods).