TY - JOUR
T1 - Measurements of mass-dependent Te isotopic variation by hydride generation MC-ICP-MS
AU - Wasserman, N. L.
AU - Johnson, T. M.
N1 - We thank Dr Sarah Hayes (USGS) for supplying the mine tailing samples, Dr David Smith (USGS) for providing the USGS soil samples, Professor Noah Planavsky for supplying samples CLG-1 and CLRD-3.0 and Professor Craig Lundstrom (UIUC) for contributing the USGS standard reference materials. In addition, we would like to acknowledge help from the late Dr Thomas Bullen (USGS), who provided the 120Te and 124Te spike solutions from a source unknown to the authors. This material is based upon work supported by the National Science Foundation under Grant No. NSF EAR 16-60600.
PY - 2020/2
Y1 - 2020/2
N2 - Tellurium (Te) stable isotope measurements have the potential to serve as tracers of Te mobility and redox conditions in modern and ancient environments. Here, we present a method to measure Te isotope ratios by MC-ICP-MS utilizing a hydride generation system to efficiently deliver Te to the plasma, in combination with a 120Te-124Te double spike. This approach allows for precise δ130Te/126Te (2σ: 0.09‰) measurements while using less than 8.75 ng of natural Te. Although hydride generation methods usually produce higher sensitivity than more conventional methods, for Te, the sensitivity is similar, on our instrument, to that achieved using a desolvating nebulizer. Nonetheless, hydride generation has an advantageous ability to exclude interfering elements such as Ba and allow analysis of samples without chemical separation of Te in some cases. We also demonstrate successfully a modified ion exchange procedure to separate various matrix components and isobaric interferences from Te in natural sediments. Analyses of multiple digestions of USGS standard reference materials, mine tailings, ancient sediments, and soils utilizing this approach show the largest spread in terrestrial Te isotopic composition to date (δ130Te/126Te ∼ 1.21‰) and a lack of detectable mass-independent fractionation.
AB - Tellurium (Te) stable isotope measurements have the potential to serve as tracers of Te mobility and redox conditions in modern and ancient environments. Here, we present a method to measure Te isotope ratios by MC-ICP-MS utilizing a hydride generation system to efficiently deliver Te to the plasma, in combination with a 120Te-124Te double spike. This approach allows for precise δ130Te/126Te (2σ: 0.09‰) measurements while using less than 8.75 ng of natural Te. Although hydride generation methods usually produce higher sensitivity than more conventional methods, for Te, the sensitivity is similar, on our instrument, to that achieved using a desolvating nebulizer. Nonetheless, hydride generation has an advantageous ability to exclude interfering elements such as Ba and allow analysis of samples without chemical separation of Te in some cases. We also demonstrate successfully a modified ion exchange procedure to separate various matrix components and isobaric interferences from Te in natural sediments. Analyses of multiple digestions of USGS standard reference materials, mine tailings, ancient sediments, and soils utilizing this approach show the largest spread in terrestrial Te isotopic composition to date (δ130Te/126Te ∼ 1.21‰) and a lack of detectable mass-independent fractionation.
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U2 - 10.1039/c9ja00244h
DO - 10.1039/c9ja00244h
M3 - Article
AN - SCOPUS:85079574352
SN - 0267-9477
VL - 35
SP - 307
EP - 319
JO - Journal of Analytical Atomic Spectrometry
JF - Journal of Analytical Atomic Spectrometry
IS - 2
ER -