Precise Measurement of Tellurium Isotope Ratios in Terrestrial Standards Using a Multiple Collector Inductively Coupled Plasma Mass Spectrometry

Precise tellurium (Te) isotope ratio measurement using mass spectrometry is a challenging task for many decades. In this paper, Te isotope ratio measurements using multi-collector inductively coupled plasma mass spectrometry (MC–ICP–MS) in terrestrial Te standards have been reported. Newly developed Faraday cup with 10(12) Ω resistor is used to measure low abundance (120)Te, whereas the 10(11) Ω resistor is used to measure other Te isotopes. The relative standard deviation obtained for Te isotope ratio measurement by Faraday cups of (120)Te/(128)Te [0.002907(05)], (122)Te/(128)Te [0.079646(10)], (123)Te/(128)Te [0.027850(07)], (125)Te/(128)Te [0.221988(09)], (126)Te/(128)Te [0.592202(20)], and (130)Te/(128)Te [1.076277(30)] were 0.140%, 0.014%, 0.026%, 0.005%, 0.004%, and 0.004%, respectively. The measured isotope ratio results are compared with previous results obtained by thermal ionization mass spectrometry (TIMS), negative thermal ionization mass spectrometry (N–TIMS), and MC–ICP–MS, showing an improvement in the precision about one order of magnitude for (120)Te/(128)Te ratio. The present study shows better precision for Te isotope ratios compared to earlier studies.