This study investigates the behavior of Mo and Mo isotopes (δ^(98)Mo) in shales following leaching with HCl and HNO_(3) with the aim of simplifying the shale dissolution procedure.Up to 6%of the Mo was lost and the M...This study investigates the behavior of Mo and Mo isotopes (δ^(98)Mo) in shales following leaching with HCl and HNO_(3) with the aim of simplifying the shale dissolution procedure.Up to 6%of the Mo was lost and the Mo isotopes were unaffected when shales were leached using 9 M HCl after ashing.Bulk sample digestion or leaching by 4 M or more concentrated HCl after ashing were all found to be acceptable and reliable approaches to the analysis of Mo isotopes in shales.After black shale (CAGS-BS) was leached with 2 M HCl,1 M HCl,and 9 M HNO_(3),the Mo concentration ([Mo]) in the leachate was lower and δ^(98)Mo was heavier than that obtained from bulk digestion.A Mo isotope mass-balance model showed that the δ^(98)Mo in the residues was lighter than the δ^(98)Mo from the bulk digestion of CAGS-BS and of crustal igneous rocks.No more Mo was lost,nor did Mo isotope fractionation,if the double spike was added before rather than after ashing and followed by bulk digestion or leaching with 9 M HCl.For efficiency,leaching using 4 M or more concentrated HCl after ashing is preferred for Mo isotope measurements.展开更多
Here we report iron(Fe) isotopic data of three pure Fe solution standards(IRMM-014, GSB Fe, and NIST3126a) and five widely used geological reference materials(RMs) from the United States Geological Survey and Geologic...Here we report iron(Fe) isotopic data of three pure Fe solution standards(IRMM-014, GSB Fe, and NIST3126a) and five widely used geological reference materials(RMs) from the United States Geological Survey and Geological Survey of Japan obtained on a Neptune Plus multi-collector–inductively coupled plasma–mass spectrometer(MC-ICP-MS) in our laboratory over the past 3 years. The instrumental mass bias was corrected by three independent methods: sample-standard bracketing(SSB),Ni doping + SSB, and ^(57)Fe–^(58)Fe double spike + SSB.Measurements reveal that both the Ni doping and double spike methods helped calibrate short-term fluctuations in mass bias. Collectively, almost all measurements of RMs yielded δ^(56)Fe within ± 0.05 of recommended values,provided that each sample was measured four times on MC-ICP-MS. For the first time, new recommended values for NIST SRM3126a are reported(δ^(56)Fe = 0.363 ± 0.006,2SE, 95% CI; and δ^(57)Fe = 0.534 ± 0.010, 2SE).展开更多
基金supported by the National Key Research & Development Program of China(No.2019YFA0708404)the National Natural Science Foundation of China(Nos.41973020,41303002,41873027)。
文摘This study investigates the behavior of Mo and Mo isotopes (δ^(98)Mo) in shales following leaching with HCl and HNO_(3) with the aim of simplifying the shale dissolution procedure.Up to 6%of the Mo was lost and the Mo isotopes were unaffected when shales were leached using 9 M HCl after ashing.Bulk sample digestion or leaching by 4 M or more concentrated HCl after ashing were all found to be acceptable and reliable approaches to the analysis of Mo isotopes in shales.After black shale (CAGS-BS) was leached with 2 M HCl,1 M HCl,and 9 M HNO_(3),the Mo concentration ([Mo]) in the leachate was lower and δ^(98)Mo was heavier than that obtained from bulk digestion.A Mo isotope mass-balance model showed that the δ^(98)Mo in the residues was lighter than the δ^(98)Mo from the bulk digestion of CAGS-BS and of crustal igneous rocks.No more Mo was lost,nor did Mo isotope fractionation,if the double spike was added before rather than after ashing and followed by bulk digestion or leaching with 9 M HCl.For efficiency,leaching using 4 M or more concentrated HCl after ashing is preferred for Mo isotope measurements.
基金supported by the National Natural Science Foundation of China(41473016)the State Key Laboratory of Geological Processes and Mineral Resources
文摘Here we report iron(Fe) isotopic data of three pure Fe solution standards(IRMM-014, GSB Fe, and NIST3126a) and five widely used geological reference materials(RMs) from the United States Geological Survey and Geological Survey of Japan obtained on a Neptune Plus multi-collector–inductively coupled plasma–mass spectrometer(MC-ICP-MS) in our laboratory over the past 3 years. The instrumental mass bias was corrected by three independent methods: sample-standard bracketing(SSB),Ni doping + SSB, and ^(57)Fe–^(58)Fe double spike + SSB.Measurements reveal that both the Ni doping and double spike methods helped calibrate short-term fluctuations in mass bias. Collectively, almost all measurements of RMs yielded δ^(56)Fe within ± 0.05 of recommended values,provided that each sample was measured four times on MC-ICP-MS. For the first time, new recommended values for NIST SRM3126a are reported(δ^(56)Fe = 0.363 ± 0.006,2SE, 95% CI; and δ^(57)Fe = 0.534 ± 0.010, 2SE).
