A critical review on isotopic fractionation correction methods for accurate isotope amount ratio measurements by MC-ICP-MS

Abstract

Proper correction of mass-dependent and mass-independent isotopic fractionation is crucial to obtain accurate isotope amount ratios by multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS).

Determination of Gallium Isotopic Compositions in Reference Materials

“…This method was first proposed by Maréchal et al () and has been successfully used for high precision isotope ratio measurements of Zn, Cu (Mason et al , Baxter et al , Peel et al , Hou et al ), Ga (Zhang et al ) and Sr (Yang et al ). The main advantage of this model is that short‐term fluctuations in the instrument mass bias during bracketing calibrators are corrected through the use of spiked Cu in both bracketing calibrators and samples (Yang et al , Zhang et al ). Thus, the pure Cu solution NIST SRM 3114 was quantitatively added to the bracketing calibrators and the purified samples to achieve the equivalent mass fraction of the analyte Ga at 100 ng g −1 .…”

Copper Isotope Ratio Measurements of Cu-Dominated Minerals Without Column Chromatography Using MC-ICP-MS

“…In recent years, the Cu isotopic ratios can be measured by MC-ICP-MS with higher analytical accuracy and precision compared with TIMS (Maréchal et al, 1999 ; Zhu et al, 2000 , 2002 ; Archer and Vance, 2004 ). However, MC-ICP-MS suffers from much larger mass bias/isotope fractionation (mass-dependent and mass-independent fractionation) than TIMS in the measurement of isotopic ratios, and thus selection of the suitable mass bias correction method is very important for different isotopes (Yang, 2009 ; Yang et al, 2018 ). For copper isotope ratios determination, the most commonly used models to improve the analysis accuracy and precision include the straightforward standard-sample bracketing (SSB), combined standard-sample bracketing with internal standard (C-SSBIN) and regression mass bias correction (Maréchal et al, 1999 ; Zhu et al, 2000 , 2002 ; Archer and Vance, 2004 ; Yang, 2009 ; Larner et al, 2011 ; Hou et al, 2016 ; Yang et al, 2018 ).…”

“…However, MC-ICP-MS suffers from much larger mass bias/isotope fractionation (mass-dependent and mass-independent fractionation) than TIMS in the measurement of isotopic ratios, and thus selection of the suitable mass bias correction method is very important for different isotopes (Yang, 2009 ; Yang et al, 2018 ). For copper isotope ratios determination, the most commonly used models to improve the analysis accuracy and precision include the straightforward standard-sample bracketing (SSB), combined standard-sample bracketing with internal standard (C-SSBIN) and regression mass bias correction (Maréchal et al, 1999 ; Zhu et al, 2000 , 2002 ; Archer and Vance, 2004 ; Yang, 2009 ; Larner et al, 2011 ; Hou et al, 2016 ; Yang et al, 2018 ). For example, the pioneering work of Maréchal et al ( 1999 ) displayed that instrumental mass bias could be corrected by combining Zn-doped with SSB method, so it was possible to obtain precision of better than 0.1‰ for Cu isotopic ratio using MC-ICP-MS. Zhu et al ( 2000 , 2002 ) and Archer and Vance ( 2004 ) also determined the Cu isotopic ratios using this approach.…”

Absolute isotope ratios of carbon dioxide – a feasibility study

“…28 That method has been used in the work presented here. Other methods of obtaining absolute isotope ratios are listed and discussed in the overview of Yang et al 29 The main idea of the gravimetric mixture approach is to use isotopically altered parent materials and to prepare binary blends from them. With the knowledge of the masses of the parent materials and the measured ion intensities, the needed K-factors can be calculated.…”