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    National Tsing Hua University Institutional Repository > 歷任校長 > 沈君山 (1994-1997) > 期刊論文 >  Detecting Small Isotopic Shifts in Two-isotope Elements Using Thermal Ionization Mass Spectrometry


    Please use this identifier to cite or link to this item: http://nthur.lib.nthu.edu.tw/dspace/handle/987654321/80855


    Title: Detecting Small Isotopic Shifts in Two-isotope Elements Using Thermal Ionization Mass Spectrometry
    Authors: J.J. Shen;T. Lee;C.T. Chang
    教師: 沈君山
    Date: 1992
    Publisher: American Chemical Society
    Relation: ANALYTICAL CHEMISTRY, American Chemical Society, Volume 64, Issue 19, OCT 1 1992, Pages 2216-2220
    Keywords: RATIOS
    QUANTITIES
    PICOMOLE
    Abstract: Because two-isotope elements have no extra ratio to normalize in order to correct the instrumental mass fractionation effect, it has been difficult to measure their isotopic composition with high precision. We propose a new technique to overcome this by analyzing monooxide ions and normalizing to the oxygen isotopic ratios in order to correct the instrumental mass fractionation effect. Using LaO as an example, we were able to show that mass fractionation causes both (LaO/LaO)-La-139-O-18-La-138-O-16 and (LaO/LaO)-La-138-O-16-La-139-O-16 to vary almost linearly with (LaO/LaO)-La-139-O-18-La-139-O-16. By normalizing (LaO/LaO)-La-139-O-18-La-139-O-16 to O-18/O-16, we can detect the isotopic shift in La-138/La-139 from both (LaO/LaO)-La-139-O-18-La-138-O-16 and (LaO/LaO)-La-138-O-16-La139-O-16 with a 95 % confidence interval of +/-0.08 % while the uncorrected (LaO/LaO)-La-139-O-18-La-139-O-16 varies by more than +/-2 % and (LaO/LaO)-La-138-O-16-La-139-O-16 varies by +/-0.2 %. The ability to detect small isotopic shifts in two-isotope elements will have many applications for natural isotopic variation studies and artificial tracer work.
    Relation Link: http://pubs.acs.org/
    URI: http://nthur.lib.nthu.edu.tw/dspace/handle/987654321/80855
    Appears in Collections:[沈君山 (1994-1997)] 期刊論文
    [物理系] 期刊論文

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