Copper Isotopic Analysis in Geological and Biological Reference Materials by MC-ICP-MS

The characterisation of relative copper isotope amount ratios (delta Cu-65) helps constrain a variety of geochemical processes occurring in the geosphere, biosphere and hydrosphere. The accurate and precise determination of delta Cu-65 in matrix reference materials is crucial in the effort to validate measurement methods. With the goal of expanding the number and variety of available geological and biological materials, we have characterised the delta Cu-65 values of ten reference materials by MC-ICP-MS using C-SSBIN model for mass bias correction. SGR-1b (Green River shale), DOLT-5 (dogfish liver), DORM-4 (fish protein), TORT-3 (lobster hepatopancreas), MESS-4 (marine sediment) and PACS-3 (marine sediment) have for the first time been characterised for delta Cu-65. Additionally, four reference materials (with published delta Cu-65 values) have been characterised: BHVO-1 (Hawaiian basalt), BIR-1 (Icelandic basalt), W-2a (diabase) and Seronorm (TM) Trace Elements Serum L-1 (human serum). The reference materials measured in this study possess complex and varied matrices with copper mass fractions ranging from 1.2 mu g g(-1) to 497 mu g g(-1) and delta Cu-65 values ranging from -0.20 parts per thousand to 0.52 parts per thousand with a mean expanded uncertainty of +/- 0.07 parts per thousand (U, k = 2), covering much of the natural copper isotope variability observed in the environment.