Applicability of High-Resolution ICP-Mass Spectrometry for Isotope Ratio Measurements
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- 作者：Frank Vanhaecke ; Luc Moens ; Richard Dams ; Ioannis Papadakis and ; and Philip Taylor
- 刊名：Analytical Chemistry
- 出版年：1997
- 出版时间：January 15, 1997
- 年：1997
- 卷：69
- 期：2
- 页码：268 - 273
- 全文大小：139K
- 年卷期：v.69,no.2(January 15, 1997)
- ISSN：1520-6882
文摘
The present paper reports on the capability of high-resolution inductively coupled plasma mass spectrometry(HR-ICPMS) for the accurate and precise determinationof isotope ratios of which at least one of the isotopesinvolved is spectrally interfered when measured at lowresolution, using Cu as a typical example. When acommercially available Finnigan MAT Element high-resolution ICP-mass spectrometer operated at a resolution setting of 3000 is used, careful selection of themeasurement conditions allows a63Cu/65Cu or206Pb/207Pb isotope ratio precision of ~0.1% (RSD forn = 10)at sufficiently high count rates (
100 000 counts/s).Inthis work, Cu isotope ratios were determined both in (i)an Antarctic sediment digest and in (ii) a human serumreference material. Even at the low Cu concentrationlevelin the Antarctic sediment digests (~10 
g/L), the63Cu/65Cu isotope ratio could be measured with an RSDof
0.6% (n = 5). Although both isotopes involvedwereseverely spectrally interfered when measured at lowresolution, measurement at R = 3000 resulted inanisotope ratio that agreed within the measurement uncertainty with the expected natural isotopic abundance ratio.For the human serum reference material, the samplepreparation was limited to 10-fold dilution with 0.14 MHNO3, resulting in solutions containing ~100 g/LCu.The 63Cu/65Cu isotope ratio was measuredwith an RSDof 0.3% (n = 5) and agreed within themeasurementuncertainty with the value expected on the basis of thenatural isotopic abundances. Finally, on the basis ofthecorresponding mass spectra at R = 3000, forbothsamples an attempt was made to identify the polyatomicions that spectrally interfere with the Cu ion signals atlowresolution. For the Antarctic sediment digest, theseinterfering ions were speculatively identified as40Ar23Na+,28Si35Cl+, and23Na216O1H+for 63Cu+ and30Si35Cl+,28Si37Cl+, and23Na219F+for 65Cu+. For the humanserumreference material, the interfering signals wereattributedto 40Ar23Na+,31P16O2+, and23Na216O1H+for 63Cu+ andto32S16O21H+for 65Cu+.
100 000 counts/s).Inthis work, Cu isotope ratios were determined both in (i)an Antarctic sediment digest and in (ii) a human serumreference material. Even at the low Cu concentrationlevelin the Antarctic sediment digests (~10 g/L), the63Cu/65Cu isotope ratio could be measured with an RSDof0.6% (n = 5). Although both isotopes involvedwereseverely spectrally interfered when measured at lowresolution, measurement at R = 3000 resulted inanisotope ratio that agreed within the measurement uncertainty with the expected natural isotopic abundance ratio.For the human serum reference material, the samplepreparation was limited to 10-fold dilution with 0.14 MHNO3, resulting in solutions containing ~100 g/LCu.The 63Cu/65Cu isotope ratio was measuredwith an RSDof 0.3% (n = 5) and agreed within themeasurementuncertainty with the value expected on the basis of thenatural isotopic abundances. Finally, on the basis ofthecorresponding mass spectra at R = 3000, forbothsamples an attempt was made to identify the polyatomicions that spectrally interfere with the Cu ion signals atlowresolution. For the Antarctic sediment digest, theseinterfering ions were speculatively identified as40Ar23Na+,28Si35Cl+, and23Na216O1H+for 63Cu+ and30Si35Cl+,28Si37Cl+, and23Na219F+for 65Cu+. For the humanserumreference material, the interfering signals wereattributedto 40Ar23Na+,31P16O2+, and23Na216O1H+for 63Cu+ andto32S16O21H+for 65Cu+.