1) High-Precision Mass Spectrometry and Environment Change Laboratory (HISPEC), Department of Geosciences, National Taiwan University, Taipei 10617, Taiwan, ROC, 2) Department of Earth Sciences, University of Minnesota, Minneapolis, MN 55455, USA, 3) Géoazur, CNRS UMR6526, UNS, Parc-Valrose, 06108 Nice, France, 4) School of Geographical Sciences, Southwest University, Chongqing 400715, People’s Republic of China, 5) Institute of Geology, Vietnamese Academy of Science and Technology, Hanoi, Viet Nam, 6) Division of Evolution of Earth Environment, Graduate School of Social and Cultural Studies, Kyushu University, Japan, 7) Earth Dynamic System Research Center, National Cheng Kung University, No. 1, University Road, Tainan City 701, Taiwan, ROC, 😎 Institute of Geology and Paleontology, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria Geochimica et Cosmochimica Acta (2012), V99, pp71–86, doi: 10.1016/j.gca.2012.09.018 High-precision and high-resolution carbonate 230Th dating by MC-ICP-MS with SEM protocols Chuan-Chou Shen (1), Chung-Che Wu (1), Hai Cheng (2), R. Lawrence Edwards (2), Yu-Te Hsieh (1), Sylvain Gallet (1,3), Ching-Chih Chang (1), Ting-Yong Li (1,4), Doan Dinh Lam (5), Akihiro Kano (6), Masako Hori (1,7), Christoph Spötl (8) To facilitate the measurement of U–Th isotopic compositions suitable for high-precision and high-resolution 230Th dating of coral and speleothem carbonates, secondary electron multiplier (SEM) protocol techniques for multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) have been developed. The instrumental sensitivities are 1–2%, with a precision of ±1–2‰ (2σ) for abundance determination of 50–200 fg 234U (1–4 ng 238U) or 230Th. This method features chemistry refinements, improvements to procedural and instrumental blanks, spectral inference reductions, and careful consideration of non-linear SEM behavior. Measurement consistency of this MC-ICP-MS combined with previous mass spectrometric results on U–Th standards and a variety of carbonates demonstrates the validity of the SEM protocol method.