In situ simultaneous measurement of Rb–Sr/Sm–Nd or Sm–Nd/Lu–Hf isotopes in natural minerals using laser ablation multi-collector ICP-MS

Abstract

This study presents a combined methodology of simultaneously measuring Rb–Sr/Sm–Nd or Sm–Nd/Lu–Hf isotopes in natural minerals by a means of two multiple collector inductively coupled plasma mass spectrometers (MC-ICP-MSs) connected to a 193 nm excimer laser ablation system. The ablated materials carried out of the HelEx cell by helium gas are split into two gas streams with different proportions into the Neptune for Sr (or Nd) analyses and Neptune Plus for Nd (or Hf) analyses. Experiments show that the different proportions of the ablated material for the Neptune and Neptune Plus MC-ICP-MS (3 : 7, 5 : 5 and 7 : 3) do not show any significant bias for the Sr–Nd isotopes on apatite and loparite within analytical uncertainties. Therefore, we conclude that this technique is suitable to simultaneously measure Rb–Sr and Sm–Nd or Sm–Nd and Lu–Hf isotopes in natural minerals, such as apatite, perovskite, loparite and eudialyte for Sr–Nd isotopes as well as eudialyte and zirconolite for Nd–Hf isotopes.