Molybdenum concentrations measured in eleven USGS geochemical reference materials by isotope dilution thermal ionisation mass spectrometry

Molybdenum concentrations in eleven USGS geochemical reference materials AG V-1, BCR-1, BHVO-1, BIR-1, DNC-1, DTS-1, G-2, GSP-1, MAG-1, PCC-1 and W-2 w ere measured by isotope dilution thermal ionisation mass spectrometry (ID-T IMS). In every case but one, the concentrations determined in this study we re significantly lower than the current consensus values. Molybdenum concen trations determined by ID-TIMS are inherently more accurate and precisions may be up to an order of magnitude higher than those measured by other anal ytical techniques.