Evaluation of UV-fs-LA-MC-ICP-MS for Precise in situ Copper Isotopic Microanalysis of Cubanite

Matrix and energy effects during in-situ determination of Cu isotope ratios by ultraviolet-femtosecond laser ablation multicollector inductively coupled plasma mass spectrometry

“…With the exception of native Cu and cuprite for which the δ 65 Cu values could be reproduced within the analytical uncertainty, Ikehata et al [6] and Ikehata and Hirata [7] noticed a more than 2‰ offset in δ 65 Cu between solution and in situ measurements of Cu isotopes in Cu sulfides. Thus, previous studies [5][6][7] employed a matrix-matched calibration to achieve accurate results and a precision of better than 0.12‰ and 0.14‰ (2SD), respectively. Subsequently, the in situ measurements of Cu-isotopes are restricted to employing homogeneous mineral standards for each Cumineral [7], which are generally difficult to find.…”

“…It has two stable isotopes that fractionate, for example through changes in redox or pH conditions during the formation of porphyry copper deposits and during supergene processes [1][2][3]. As this isotopic signature can be followed on a mineral scale, several studies [4][5][6][7][8][9] have attempted to determine the Cu isotopic composition through in situ measurements using laser ablation (LA) coupled to multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The first LA-MC-ICP-MS measurements of Cu isotopes were performed by Jackson and Guenther [4] using a 266 nm Nd:YAG laser.…”

“…Graham et al [5] introduced a Zn standard solution for the instrumental mass bias correction of the Cu isotope measurement. Ikehata et al [6] and Ikehata and Hirata [7] employed dry plasma conditions and the instrumental mass bias was corrected by standard-sample-standard bracketing (SSB) for measurements of Cu-metals and copper rich minerals. With the exception of native Cu and cuprite for which the δ 65 Cu values could be reproduced within the analytical uncertainty, Ikehata et al [6] and Ikehata and Hirata [7] noticed a more than 2‰ offset in δ 65 Cu between solution and in situ measurements of Cu isotopes in Cu sulfides.…”

“…Ikehata et al [6] and Ikehata and Hirata [7] employed dry plasma conditions and the instrumental mass bias was corrected by standard-sample-standard bracketing (SSB) for measurements of Cu-metals and copper rich minerals. With the exception of native Cu and cuprite for which the δ 65 Cu values could be reproduced within the analytical uncertainty, Ikehata et al [6] and Ikehata and Hirata [7] noticed a more than 2‰ offset in δ 65 Cu between solution and in situ measurements of Cu isotopes in Cu sulfides. Thus, previous studies [5][6][7] employed a matrix-matched calibration to achieve accurate results and a precision of better than 0.12‰ and 0.14‰ (2SD), respectively.…”

“…Thus, previous studies [5][6][7] employed a matrix-matched calibration to achieve accurate results and a precision of better than 0.12‰ and 0.14‰ (2SD), respectively. Subsequently, the in situ measurements of Cu-isotopes are restricted to employing homogeneous mineral standards for each Cumineral [7], which are generally difficult to find.…”