TY - JOUR
T1 - Precise isotope analysis of nanogram-level Pb for natural rock samples without use of double spikes
AU - Kuritani, Takeshi
AU - Nakamura, Eizo
N1 - Funding Information:
We are grateful to Takuya Moriguti, Akio Makishima, Tetsuya Yokoyama, Ryoji Tanaka, and Tomohiro Usui for constructive discussions and technical assistance throughout this study. Constructive reviews and comments by M.F. Thirlwall and final reading by I.H. Campbell significantly improved the manuscript. We thank C. Sakaguchi, K. Kobayashi, H. Takei, and all the other members of Pheasant Memorial Laboratory for Geochemistry and Cosmochemistry at ISEI for their encouragements and for useful discussions. C.J. Allègre and C. Göpel are also thanked for editorial handlings. This work was supported by the Japanese Society for the Promotion of Science for Japan Junior Scientists (T.K.), and the Ministry of Education, Culture, Sports, Science and Technology (E.N.). [CA]
PY - 2002
Y1 - 2002
N2 - A simple technique has been developed for the precise analysis of lead isotope in natural rock samples by thermal ionization mass spectrometry (TIMS). Two-stage column chromatography, using 100 and 10 μl columns, was used to minimize the amounts of impurities in separated lead samples. This dramatically improved the reproducibility of mass fractionation during mass spectrometry using an ion emitter made of a mixture of silicic acid and phosphoric acid. This improvement made it possible to precisely determine the Pb isotopic compositions of very small sample sizes, employing "zero-time correction" for mass discrimination, without requiring a double-spike technique. Using the present method, analytical reproducibility of 208Pb/204Pb of 0.02% and 0.06% (2σ) was attained for 100 and 1 ng of Pb, respectively, separated from natural rock samples. Furthermore, we obtained a reproducibility of 0.06% (2σ) for 208Pb/204Pb for 10 ng of Pb separated from GSJ JP-1 (peridotite), in which the Pb concentration was 0.09 ppm. The measured isotope compositions of USGS standard rocks AGV-1 and BCR-1 were comparable with the published values using the double-spike technique. These observations suggest that our simple technique is reliable in terms of both accuracy and precision for the determination of the Pb isotopic compositions of natural rock samples irrespective of rock chemistry and sample sizes from 1 to 100 ng of Pb.
AB - A simple technique has been developed for the precise analysis of lead isotope in natural rock samples by thermal ionization mass spectrometry (TIMS). Two-stage column chromatography, using 100 and 10 μl columns, was used to minimize the amounts of impurities in separated lead samples. This dramatically improved the reproducibility of mass fractionation during mass spectrometry using an ion emitter made of a mixture of silicic acid and phosphoric acid. This improvement made it possible to precisely determine the Pb isotopic compositions of very small sample sizes, employing "zero-time correction" for mass discrimination, without requiring a double-spike technique. Using the present method, analytical reproducibility of 208Pb/204Pb of 0.02% and 0.06% (2σ) was attained for 100 and 1 ng of Pb, respectively, separated from natural rock samples. Furthermore, we obtained a reproducibility of 0.06% (2σ) for 208Pb/204Pb for 10 ng of Pb separated from GSJ JP-1 (peridotite), in which the Pb concentration was 0.09 ppm. The measured isotope compositions of USGS standard rocks AGV-1 and BCR-1 were comparable with the published values using the double-spike technique. These observations suggest that our simple technique is reliable in terms of both accuracy and precision for the determination of the Pb isotopic compositions of natural rock samples irrespective of rock chemistry and sample sizes from 1 to 100 ng of Pb.
KW - Double spikes
KW - Isotope analysis
KW - Pb
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U2 - 10.1016/S0009-2541(02)00004-9
DO - 10.1016/S0009-2541(02)00004-9
M3 - Article
AN - SCOPUS:0036072442
VL - 186
SP - 31
EP - 43
JO - Chemical Geology
JF - Chemical Geology
SN - 0009-2541
IS - 1-2
ER -