High-precision copper isotopic analysis using a Nu Sapphire MC-ICP-MS.

Here we present an analytical method for Cu isotopic measurement using standard-sample bracketing on a Nu Sapphire multi-collector inductively coupled plasma mass spectrometer. The effects of Cu concentration and HNO3 molarity mismatch between the standard and the sample, as well as the presence of matrix elements have been evaluated. Intermediate precision of better than ±0.030‰ for δ65Cu (2SD) was routinely obtained on NIST SRM 3114 and NWU-Cu-A. Accurate measurements were achieved when CNa/CCu < 0.5, CTi/CCu, CFe/CCu and CCo/CCu < 1, CNi/CCu < 3 and CZn/CCu < 10. High-precision Cu isotopic data were determined for nineteen geological reference materials, including igneous rocks, sedimentary rocks, metamorphic rocks and chalcopyrite, with an overall range of ∼0.44‰ (−0.056‰ to 0.384‰), nearly 15 times the current analytical precision. The Cu isotopic data of these reference materials can be used for future interlaboratory comparisons. [ABSTRACT FROM AUTHOR]