Determination of Precise and Accurate 51V/50V Isotope Ratios by Multi-Collector ICP-MS, Part 2: Isotopic Composition of Six Reference Materials plus the Allende Chondrite and Verification Tests

We present the first measurements of vanadium (V) stable isotopes for six reference materials - USGS PCC-1, BHVO-2, BCR-2, BIR-1a, GSP-2 and AGV-2 plus the widely available carbonaceous chondrite Allende. We present standard addition and matrix spiking tests to assess the robustness and reproducibility of our data. Standard addition utilised an enriched V-50 solution designated VISSOX (Vanadium Isotope Standard Solution OXford). We further assessed the veracity of the method by spiking collected sample matrices with the same amount of a V standard solution, whose isotopic composition was defined as 0 parts per thousand. Standard addition and matrix spiking tests recorded no appreciable artificial isotope fractionation. We estimate that the best currently attainable long-term reproducibility of stable V-51/V-50 isotope measurements in complex matrices is 0.15 parts per thousand, which is in the same order as the reproducibility achievable with standard solutions. Finally, a large range of similar to 1.2 parts per thousand in stable V isotopic composition was documented, with similar to 0.5 parts per thousand of that variation in high temperature igneous materials alone. The range and resolving power of V stable isotopes, with respect to igneous material, compared favourably with the magnitude of fractionation reported for other non-traditional stable isotope systems, which bodes well for the utility of this new system.