Please use this identifier to cite or link to this item:
Title: Optimizing MC-ICP-MS with SEM protocols for determination of U and Th isotope ratios and 230Th ages in carbonates
Authors: Lin, Ke
Chiang, Hong-Wei
Lu, Yanbin
Wang, Xianfeng
Liu, Xiaokang
Keywords: U-Th Dating
Issue Date: 2019
Source: Chiang, H.-W., Lu, Y., Wang, X., Lin, K., & Liu, X. (2019). Optimizing MC-ICP-MS with SEM protocols for determination of U and Th isotope ratios and 230Th ages in carbonates. Quaternary Geochronology, 5075-90. doi:10.1016/j.quageo.2018.10
Series/Report no.: Quaternary Geochronology
Abstract: We have optimized techniques to measure uranium and thorium isotopic compositions using secondary electron multiplier (SEM) and peak-jumping protocols on a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS, Thermo Scientific Neptune Plus). This instrument is equipped with an advanced interface pump, X- skimmer cone, Jet sample cone, and desolvating nebulizer system (CETAC Aridus II) that enables overall ioni-zation and transmission efficiency up to 3% for both U and Th. Approximately 50 fg234U or 230Th can routinely yield a precision of 1–2‰ (2σ) for abundance and isotopic measurements. Non-linear behavior was not observed in the MasCom SEM with a retarding potential quadrupole in our MC-ICP-MS system when the beam intensity was limited to < ∼1 × 10 6 cps. We performed a series of tests to examine the influence of tuning parameters, peak shift, and operating voltage of the SEM on isotopic measurements. Results for U/Th standards are consistent with published values and demonstrate the reliability of our protocols. Lastly, the precision and accuracy of 230Th ages based on U and Th isotope ratios is presented for a variety of carbonates, including both modern and secular-equilibrium samples. For corals as young as ∼10-yr old, we have significantly reduced the procedural chemistry blanks so that only 40 mg is required to yield an analytical precision of ± 1.4 yr (2σ). All 230Th ages from modern and fossil corals and speleothems are in agreement with band counting ages.
ISSN: 1871-1014
DOI: 10.1016/j.quageo.2018.10.003
Rights: © 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (
Fulltext Permission: open
Fulltext Availability: With Fulltext
Appears in Collections:ASE Journal Articles
EOS Journal Articles

Files in This Item:
File Description SizeFormat 
Optimizing MC-ICP-MS with SEM protocols for determination of U and Th.pdf7.13 MBAdobe PDFThumbnail

Citations 20

Updated on Jul 7, 2022

Citations 20

Updated on Jul 4, 2022

Page view(s)

Updated on Aug 8, 2022

Download(s) 50

Updated on Aug 8, 2022

Google ScholarTM




Items in DR-NTU are protected by copyright, with all rights reserved, unless otherwise indicated.