Validation of multi-element isotope dilution ICPMS for the analysis of basalts (original) (raw)
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Geostandards and Geoanalytical Research, 2005
We present a multi-element technique for the simultaneous determination of twelve trace elements in geological materials by combined isotope dilution (ID) sector field inductively coupled plasmamass spectrometry (SF-ICP-MS) following simple sample digestion. In addition, the concentrations of fourteen other trace elements have been obtained using the ID determined elements as internal standards. This method combines the advantages of ID (high precision and accuracy) with those of SF-ICP-MS (multi-element capability, fast sample processing without element separation) and overcomes the most prevailing drawbacks of ICP-MS (matrix effects and drift in sensitivity). Trace element concentration data for BHVO-1 (n = 5) reproduced to within 1-3% RSD with an accuracy of 1-2% relative to respective literature values for ID values and 2-3% for all other values. We have applied this technique to the analysis of seventeen geological reference materials from the USGS, GSJ and IAG. The sample set also included the new USGS reference glasses BCR-2G, BHVO-2G and BIR-1G, as well as the MPI-DING reference glasses KL2-G and ML3B-G, and NIST SRM 612. Most data agreed within 3-4% with respective literature data. The concentration data for the USGS reference glasses agreed in most cases with respective data of the original rock powder within the combined standard uncertainty of the method (2-3%), except the U concentration of BIR-1G, which showed a three times higher concentration compared to BIR-1.
Chemical Geology, 1997
The combination of enriched isotopes and conventional elemental internal standards permits the precise determination of > 40 trace elements by ICPMS in a broad spectrum of geological matrixes. Enriched isotopes expand the suite of available reference isotopes spaced through the mass spectrum, so that the complex mass-dependent variations in sensitivity encountered during ICPMS analysis can be monitored and deconvolved. The method we have developed is straightforward, entailing simple sample preparation, instrument calibration, and data reduction procedures, as well as providing extended element coverage, improved precision, and both time and cost benefits compared to alternative analytical strategies. Analytical precision near or better than 1% RSD (relative standard deviation) is achieved for most dements with mass > 80 amu and between 1% and 4% (RSD) for elements with mass < 80 amu, while maintaining low detection limits (< 1 to < 10 ng g-l for elements with mass > 80 amu and < 10 ng g-i to 1 Ixg g-i for elements with mass < 80 amu). The subtle geochemical differences which can be resolved using this method are demonstrated by analyses of Nb, Ta, Zr, and Hf in magmas from ocean islands and subduction zones. These data reveal significant departures from chondritic Zr/Hf and Nb/Ta values, and systematic trends which are consistent with greater incompatibility of Zr relative to Hf and also of Nb relative to Ta during melting of the upper mantle. The occurrence of significantly subchondritic Zr/Hf and Nb/Ta ratios in Nb-poor subduction zone magmas, supports the notion that the depletion of high-field strength elements in subduction magmas is due to their removal from the mantle wedge by prior melting events.
Geostandards and Geoanalytical Research, 1995
Results are presented for 26 to 30 Itrace elements determined in four rock reference materials of geochemical interest: USGS Basalt BHVO-1, Rhyolite Obsidian NIST 278, Basalt NIST688, and Phosphate Rock NIST694. Determinations were made by inductively coupled plasma mass spectrometry (ICP-MS). Good agreement was obtained among solution standard comparison and standard addition analytical techniques, and among samples prepared with different dissolution methods. Generally good agreement was oblained between determined trace element values and values reported in the literature.
Chemical Geology, 1995
An inductively coupled plasma mass spectrometer (ICP-MS) coupled to a modified Nd:YAG laser has been used for the in situ determination of trace-element zonation and partition coefficients in olivines and clinopyroxenes from natural phenocryst-matrix systems. The laser produces ablation craters of 20-40-/~m diameter when operated in Q-switched mode and can provide spatial analyses of trace elements in minerals. The ICP-MS is calibrated against a synthetic trace-element glass reference material and can be used for the rapid determination of elements at low (sub-ppm) concentrations. Partition coefficients are presented for: olivine in tholeiite glass from Stapafell, Iceland; and (2) olivine and clinopyroxene in an ankaramitic basalt from Mauna Kea, Hawaii. Data are presented for 37 compatible and incompatible trace elements, including Li, B and the REE from both suites. Detection limits are typically sub-ppm, with, for example, Tm present at 7 ppb in the Icelandic olivine and Lu at 120 ppb in the Hawaiian clinopyroxene. The calculated trace-element partition coefficients differ between the two suites. Partition coefficients for olivine (D °l/~atdx ) for Li are 0.435 (Iceland) and 0.915 (Hawaii); tbr B are 0.559 (Iceland) and 0.984 (Hawaii). Other examples include uScn°l/matrix 0.24--0.273 (Iceland) and 0.225 (Hawaii); whilst D's for Cr are 0.524-0.975 (Iceland) and 2.563 (Hawaii). D °l/matrix for REE are all greater for the Hawaiian ankaramite than for the Icelandic tholeiite. The partition coefficients calculated in this study generally fall within published ranges. 0009-2541/95/$09.50
TRACE ELEMENT ANALYSIS OF BASALT BIR‐1 BY ID‐SSMS, HPLC AND LIMS
Trace element concentrations in BIR-1 basalt have been determined by isotope dilution-spark source mass spectrometry, high performance liquid chromatography and laser ionization mass spectrometry. Of particular interest are the low abundance elements Nb, Ta, Zr, Hf, Th, U, Rb, Cs for which published data vary extremely.
Journal of Analytical Atomic Spectrometry, 2010
Geochemical research into volcanic rocks often involves isotopic analysis of whole rock powders. The method of Deniel and Pin (Anal. Chim. Acta, 2001, 426, 95-103) for simultaneous isolation of strontium and lead using extraction chromatography via Sr specÔ resin was therefore adapted into a straightforward procedure for Sr and Pb isotope ratio determination by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The main focus was to reduce their rather extensive and costly cleaning procedures for resin and columns without negatively affecting data quality. It was furthermore demonstrated that non-quantitative Sr and Pb recoveries do not compromise the quality of the isotope data obtained and that no Pb isotopic fractionation occurs on the Sr specÔ resin. The accuracy of the analyses was assessed by monitoring rock reference materials. GSJ basalt JB-2, commonly regarded as the most homogeneous Pb isotopic rock reference material, hereby produced one anomalous Pb isotopic composition out of eight analyses, suggesting that JB-2 might also be affected by nugget contamination.
Initial Reports of the Deep Sea Drilling Project, 82, 1985
Sr and Nd isotopic composition of 23 basalts from Sites 556-559 and 561-564. are reported. The 87 Sr/ 86 Sr ratios in fresh glasses and leached whole rocks range from 0.7025 to 0.7034 and are negatively correlated with the initial 143 Nd/ 144 Nd compositions, which range from 0.51315 to 0.51289. The Sr and Nd isotopic compositions (in glasses or leached samples) lie within the fields of mid-ocean ridge basalts (MORB) and ocean island basalts (OIB) from the Azores on the Nd-Sr mantle array/fan plot. In general, there is a correlation between the trace element characteristics and the 143 Nd/ 144 Nd composition (i.e., samples with Hf/Ta > 7 and (Ce/Sm) N < 1 [normal-MORB] have initial 143 Nd/ 144 Nd > 0.51307, whereas samples with Hf/Ta < 7 and (Ce/Sm) N > 1 (enriched-MORB) have initial 143 Nd/ 144 Nd compositions < 0.51300). A significant deviation from this general rule is found in Hole 558, where the N-MORB can have, within experimental limits, identical isotopic compositions to those found in associated E-MORB. The plume-depleted asthenosphere mixing hypothesis of Schilling (1975), White and Schilling (1978) and Schilling et al. (1977) provides a framework within which the present data can be evaluated. Given the distribution and possible origins of the chemical and isotopic heterogeneity observed in Leg 82 basalts, and some other basalts in the area, it would appear that the Schilling et al. model is not entirely satisfactory. In particular, it can be shown that trace element data may incorrectly estimate the plume component and more localized mantle heterogeneity (both chemical and isotopic) may be important.
Long‐Term Observations of Isotope Ratio Accuracy and Reproducibility Using Quadrupole ICP‐MS
Geostandards and Geoanalytical Research, 2010
High precision isotope ratio and trace element determination can be achieved with modern quadrupole ICP‐MS provided that short and long‐term instrument performance is accurately monitored. Here we present results for the isotope ratios 6Li/7Li, 147Sm/149Sm, 160Dy/161Dy, 207Pb/206Pb, 208Pb/206Pb, 206Pb/204Pb and 235U/238U with which we determined long‐term isotope ratio stability of relevance to both trace element and isotope determination. With respect to trace element determination, we first present long‐term observations regarding oxide formation rates of Ba and Nd on light REE and heavy REE, as well as Zr on Ag. These showed good correlations and could be used to correct effectively the interference. The efficacy of this correction was demonstrated with analyses of the rock reference material BHVO‐2 at both low and high oxide formation rates. Next, we studied the long‐term reproducibility of a Dy isotope ratio that was measured to correct for the isobaric interference on Gd. It w...
Using high-precision inductively coupled plasma mass spectrometry (ICP–MS), we measured 40 elements in basalts sampled by diamond micro-drills to evaluate the effectiveness of different digestion methods and the reproducibility of elemental analysis for different sample sizes from 5 mg to 100 mg. The results indicate that those elements that are most suitable for geochemical characterization, such as rare earth elements (REE), high-field strength elements (HFSE) and certain mobile elements (Rb, Sr, Th, U), show excellent reproducibility with an average relative standard deviation (RSD) of 3% between open-beaker and pressured ‘bomb’ digestion methods. This observation rules out the presence of refractory phases such as zircon, which can only dissolve in pressured ‘bombs’, and suggests that the results from open-beaker digestion are reliable. The ICP–MS data for powders of different weights ranging from 10 to 100 mg collected from two fine-grained basalt artefacts display excellent reproducibility, with a RSD of 5% for the most important elements. The reproducibility is reduced when including the 5 mg weight fraction (RSD of ~2–9%), which is still sufficient for archaeological applications. Our results demonstrate the usefulness of 10 mg samples for elemental measurement, which is valuable for geochemical characterization and sourcing of fine-grained basalt artefacts from museum collections that require minimal destructive sampling.
Icp-MS Analysis of Basalt BIR-1 for Trace Elements
Geostandards and Geoanalytical Research, 1994
The concentrations of 27 trace elements in the basalt BIR-1, as well as in other mafic rock reference materials, have been determined by ICP-MS, using pure elemental solutions for external calibration and standard additions. Concentrations of rare earth elements in BIR-1 for the new ICP-MS data, agree with compiled values, and previous ID-SSMS results, whereas ICP-MS data on HFSE's are systematically higher by about 40% to 70% than ID-SSMS, but are consistent with data generated at other ICP-MS laboratories.