Titanium Isotope Analysis of Igneous Reference Materials using a Double-spike MC-ICP-MS Method  

作　　者：LI Jin TANG Suohan ZHU Xiangkun MA Jianxiong ZHAO Xinmiao 

机构地区：[1]MNR Key Laboratory of Isotope Geology,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China [2]State Key Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China

出　　处：《Acta Geologica Sinica(English Edition)》2022年第2期517-524,共8页地质学报（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Project Nos.41473005,41973020,41873027)。

摘　　要：Ti separation was achieved by ion-exchange chromatography using Bio-Rad AG 1-X8 anion-exchange and DGA resins.For high-Fe/Ti and high-Mg/Ti igneous samples,a three-column procedure was required,whereas a two-column procedure was used for low-Fe/Ti and low-Mg/Ti igneous samples.The Ti isotopes were analysed by MC-ICP-MS,and instrumental mass bias was corrected using a ^(47)Ti-^(49)Ti double-spike technique.The ^(47)Ti-^(49)Ti double-spike and SRM 3162a were calibrated using SRM 979-Cr,certificated value ^(53)Cr/^(52)Crt rue=0.11339.Isobaric interference was evaluated by analysing Alfa-Ti doped with Na,Mg,Ca,and Mo,and results indicate that high concentrations of Na and Mg have no significant effect on Ti isotope analyses;however,Ca and Mo interferences lead to erroneousδ^(49/47)Ti values when Ca/Ti and Mo/Ti ratios exceed 0.01 and 0.1,respectively.Titanium isotopic compositions were determined for 12 igneous reference materials,BCR-2,BHVO-2,GBW07105,AGV-1,AGV-2,W-2,GBW07123,GBW07126,GBW07127,GBW07101,JP-1,and DTS-2b.Samples yieldδ^(49/47)Ti(‰)of−0.035±0.022,−0.038±0.031,0.031±0.022,0.059±0.038,0.044±0.037,0.000±0.015,0.154±0.044,−0.044±0.018,0.010±0.022,0.064±0.043,0.169±0.034,and−0.047±0.025(relative to OL-Ti,±2SD),respectively;of which isotopic compositions of DTS-2b,JP-1,GBW07101,GBW07105,GBW07123,GBW07126,and GBW07127 are reported for the first time.Standard Alfa-Ti was analysed repeatedly over a ten-month period,indicating a reproducibility of±0.047(2SD)forδ^(49/47)Ti,similar to the precisions obtained for geochemical reference materials.

关 键 词：Ti isotope double-spike mass bias correction MC-ICP-MS reference material 

分 类 号：P597[天文地球—地球化学]