Boron and Oxygen Isotope Composition of Certified Reference Materials NIST SRM 610/612 and Reference Materials JB-2 and JR-2

We present data on the concentration, the isotope composition and the homogeneity of boron in NIST silicate glass reference materials SRM 610 and SRM 612, and in powders and glasses of geological reference materials JB-2 (basalt) and JR-2 (rhyolite). Our data are intended to serve as references for both microanalytical and wet-chemical techniques. The δ¹¹ B compositions determined by N-TIMS and P-TIMS agree within 0.5% and compare with SIMS data within 2.5%. SIMS profiles demonstrate boron isotope homogeneity to better than δ¹¹ B = 2% for both NIST glasses, however a slight boron depletion was detected towards the outermost 200 μm of the rim of each sample wafer. The boron isotope compositions of SRM 610 and SRM 612 were indistinguishable. Glasses produced in this study by fusing JB-2 and JR-2 powder also showed good boron isotope homogeneity, both within and between different glass fragments. Their major element abundance as well as boron isotope compositions and concentrations were identical to those of the starting composition. Hence, reference materials (glasses) for the in situ measurement of boron isotopes can be produced from already well-studied volcanic samples without significant isotope fractionation. Oxygen isotope ratios, both within and between wafers, of NIST reference glasses SRM 610 and SRM 612 are uniform. In contrast to boron, significant differences in oxygen isotope compositions were found between the two glasses, which may be due to the different amounts of trace element oxides added at ten-fold different concentration levels to the silicate matrix.     

A Compilation of New and Published Major and Trace Element Data for NIST SRM 610 and NIST SRM 612 Glass Reference Materials

Microanalytical trace element techniques (such as ion probe or laser ablation ICP-MS) are hampered by a lack of well characterized, homogeneous standards. Two silicate glass reference materials produced by National Institute of Standards and Technology (NIST), NIST SRM 610 and NIST SRM 612, have been shown to be homogeneous and are spiked with up to sixty one trace elements at nominal concentrations of 500 μg g-1 and 50 μg g-1 respectively. These samples (supplied as 3 mm wafers) are equivalent to NIST SRM 611 and NIST SRM 613 respectively (which are supplied as 1 mm wafers) and are becoming more widely used as potential microanalytical reference materials. NIST however, only certifies up to eight elements in these glasses. Here we have compiled concentration data from approximately sixty published works for both glasses, and have produced new analyses from our laboratories. Compilations are presented for the matrix composition of these glasses and for fifty eight trace elements. The trace element data includes all available new and published data, and summaries present the overall average and standard deviation, the range, median, geometric mean and a preferred average (which excludes all data outside ± one standard deviation of the overall average). For the elements which have been certified, there is a good agreement between the compiled averages and the NIST data. This compilation is designed to provide useful new working values for these reference materials.     

Lead Isotope Homogeneity of NIST SRM 610 and 612 Glass Reference Materials: Constraints from Laser Ablation Multicollector ICP-MS (LA-MC-ICP-MS) Analysis

This contribution presents data for laser ablation multicollector ICP‐MS (LA‐MC‐ICP‐MS) analyses of NIST SRM 610 and 612 glasses with the express purpose of examining the Pb isotope homogeneity of these glasses at the ～ 100 μm spatial scale, relevant to in situ analysis. Investigation of homogeneity at these scales is important as these glasses are widely used as calibrators for in situ measurements of Pb isotope composition. Results showed that at the levels of analytical uncertainty obtained, there was no discernable heterogeneity in Pb isotope composition of NIST SRM 610 and also most probably for NIST SRM 612. Traverses across the ～ 1.5 mm glass wafers supplied by NIST, consisting of between 75 and 133 individual measurements, showed no compositional outliers at the two standard deviation level beyond those expected from population statistics. Overall, the measured Pb isotope ratios from individual traverses across NIST SRM 610 and 612 wafers closely approximate single normally‐distributed populations, with standard deviations similar to the average internal uncertainty for individual measurement blocks. Further, Pb isotope ratios do not correlate with Tl/Pb ratios measured during the analysis, suggesting that regions of volatile element depletion (marked by low Tl/Pb) in these glasses are not associated with changes in Pb isotope composition. For NIST SRM 610 there also appeared to be no variation in Pb isotope composition related to incomplete mixing of glass base and trace element spike during manufacture. For NIST SRM 612 there was some dispersion of measured ratios, including some in a direction parallel to the expected mixing line for base‐spike mixing. However, there was no significant correlation parallel to the mixing line. At this time this cannot be unequivocally demonstrated to result from glass heterogeneity, but it is suggested that NIST SRM 610 be preferred for standardising in situ Pb isotope measurements. Data from this study also showed significantly better accuracy and somewhat better precision for ratios corrected for mass bias by external normalisation to Pb isotope ratios measured in bracketing calibrators compared to mass bias corrected via internal normalisation to measured ²⁰⁵Tl/²⁰³Tl, although the Tl isotopic composition of both glasses appears to be homogeneous.     

Determination of Selenium Concentrations in NIST SRM 610, 612, 614 and Geological Glass Reference Materials Using the Electron Probe, LA-ICP-MS and SHRIMP II

A combination of EMPA, sensitive high resolution ion microprobe (SHRIMP II) and/or LA-ICP-MS techniques was used to measure the concentration of selenium (Se) in NIST SRM 610, 612, 614 and a range of reference materials. Our new compiled value for the concentration of Se in NIST SRM 610 is 112 ± 2 μg g⁻¹. The concentration of Se in NIST SRM 612, using NIST SRM 610 for calibration, determined using LA-ICP-MS (confirmed using SHRIMP II) was 15.2 ± 0.2 μg g⁻¹. The concentration of Se in NIST SRM 614, using LA-ICP-MS was 0.394 ± 0.012 μg g⁻¹. LA-ICP-MS determination of Se in synthetic geological glasses BCR-2G, BIR-1G, TB-1G and the MPI-DING glasses showed a range in concentrations from 0.062 to 0.168 μg g⁻¹. Selenium in the natural glass, VG2, was 0.204 ± 0.028 μg g⁻¹.     

New ID-TIMS, ICP-MS and SIMS Data on the Trace Element Composition and Homogeneity of NIST Certified Reference Material SRM 610-611

We present new concentration data for twenty four lithophile trace elements in NIST certified reference material glasses SRM 610-SRM 611 in support of their use in microanalytical techniques. The data were obtained by solution ICP-MS and isotope dilution TIMS analysis of two different sample wafers. An overall assessment of these new results, also taking into account ion probe studies that have been published in the literature, shows that these wafers can be considered to be homogeneous. Therefore, individually analysed wafers are believed to be representative of the entire batch of the SRM 610-611 glasses. Possible exceptions are the alkali metals (and a few volatile or non-lithophile trace elements). The analysed concentrations range between 370 μg g⁻¹ (Cs) and 500 μg g⁻¹ (Sr) and agree well with published values. On the basis of our new data and data recently published in the literature we propose "preferred average" values for the elements studied. These values are, within a few percent, identical to those proposed by other workers.     

Isotope Dilution Determinations of Lu,Hf, Zr,Ta and W,and Hf Isotope Compositions of NIST SRM 610 and 612 Glass Wafers

Isotope dilution determinations of Lu, Hf, Zr, Ta and W are reported for nine test portions (five for W) of NIST SRM 610 and 612 glass wafers. Additionally, all test portions were analysed for their Hf isotope compositions. In general, high field strength elemental (HFSE) distributions in NIST SRM 610 and 612 were reproducible to ～± 1%, except for Zr (± 5%) in NIST SRM 612, and absolute reported concentrations agreed with previously published values, but with higher precision. The slightly worse reproducibility of Zr in NIST SRM 612 compared to other HFSE is interpreted to result from analytical scatter, rather than sample inhomogeneity. The analyses demonstrated elemental homogeneity for both glass wafers for samples of 1–2 mg with respect to the precision of the method, i.e., ± 1% or better. Average Hf isotope compositions for both glass wafers agreed within uncertainty and the weighted average of all determinations yielded a mean ¹⁷⁶Hf/¹⁷⁷Hf ratio of 0.282111 ± 0.000009 (95% confidence level). However, although mean values for NIST SRM 610 and 612 agreed within analytical limits, NIST SRM 610 test portions showed a tendency of systematically elevated isotope composition of ～ 0.5 _?Hf units when compared to NIST SRM 612, which may indicate a slightly more radiogenic Hf isotope composition of NIST SRM 610. The results of this study suggest that NIST SRM 610 and 612 are valuable calibrators for HFSE in situ analyses within the given uncertainties.     

Analysis of Re, Au, Pd, Pt and Rh in NIST Glass Certified Reference Materials and Natural Basalt Glasses by Laser Ablation ICP-MS

A new technique for the in situ analysis of Re, Au, Pd, Pt and Rh in natural basalt glass by laser ablation (LA)-ICP-MS is described. The method involves external calibration against NIST SRM 612/613 or 614/615 glass certified reference materials, internal standardisation using Ca, and ablation with a 200 μm wide beam spot and a pulsed laser repetition rate of 50 Hz. Under these conditions, sensitivities for Re, Au, Pd, Pt and Rh analyte ions are ˜ 5000 to 100,000 cps/μg g^-1. This is sufficient to make measurements precise to ˜ 10% at the 2-10 μg g^-1 level, which is well within the range of concentrations expected in many basalts. For LA-ICP-MS calibration and a demonstration of the accuracy of the technique, concentrations of Re, Au, Pd, Pt and Rh in the NIST SRM 610/611 (˜ 1 to 50 μg g^-1), 612/613 (˜ 1 to 7 μg g^-1), 614/615 (˜ 0.2 to 2 μg g^-1) and 616/617 (˜ 0.004 to 2 μg g^-1) glasses were determined by solution-nebulisation (SN)-ICP-MS. Using the 612/613 or 614/615 glasses as calibration standards, LA-ICP-MS measurements of these elements in the other NIST glasses fell within ˜ 15% of those determined by SN-ICP-MS. Replicate LA-ICP-MS analyses of the 612/613 and 614/615 glasses indicate that, apart from certain anomalous domains, the glasses are homogeneous for Re, Au, Pd, Pt and Rh to better than 3.5%. Two LA-ICP-MS analyses of natural, island-arc basalt glasses exhibit large fractionations of Re, Au and Pd relative to Pt and Rh, compared to the relative abundances in the primitive mantle.     

Determination of Forty Two Major and Trace Elements in USGS and NIST SRM Glasses by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry

Forty two major (Na, Mg, Ti and Mn) and trace elements covering the mass range from Li to U in three USGS basalt glass reference materials BCR‐2G, BHVO‐2G and BIR‐1G were determined using laser ablation‐inductively coupled plasma‐mass spectrometry. Calibration was performed using NIST SRM 610 in conjunction with internal standardisation using Ca. Determinations were also made on NIST SRM 612 and 614 as well as NIST SRM 610 as unknown samples, and included forty five major (Al and Na) and trace elements. Relative standard deviation (RSD) of determinations was below 10% for most elements in all the glasses under investigation. Consistent exceptions were Sn and Sb in BCR‐2G, BHVO‐2G and BIR‐1G. For BCR‐2G, BHVO‐2G and BIR‐1G, clear negative correlations on a logarithmic scale exist between RSD and concentration for elements lower than 1500 μg g^‐1 with logarithmic correlation coefficients between ‐0.75 and ‐0.86. There is also a clear trend of increasing RSD with decreasing concentration from NIST SRM 610 through SRM 612 to SRM 614. These suggest that the difference in the scatter of apparent element concentrations is not due to chemical heterogeneity but reflects analytical uncertainty. It is concluded that all these glasses are, overall, homogeneous on a scale of 60 μm. Our first results on BHVO‐2G and BIR‐1G showed that they generally agreed with BHVO‐2/BHVO‐1 and BIR‐1 within 10% relative. Exceptions were Nb, Ta and Pb in BHVO‐2G, which were 14‐45% lower than reference values for BHVO‐2 and BHVO‐1. Be, Ni, Zn, Y, Zr, Nb, Sn, Sb, Gd, Tb, Er, Pb and U in BIR‐1G were also exceptions. However, of these elements, Be, Nb, Sn, Sb, Gd, Tb, Pb and U gave results that were consistent within an uncertainty of 2s between our data and BIR‐1 reference values. Results on NIST SRM 612 agreed well with published data, except for Mg and Sn. This was also true for elements with m/z 85 (Rb) in the case of NIST SRM 614. The good agreement between measured and reference values for Na and Mg in BCR‐2G, BHVO‐2G and BIR‐1G, and for Al and Na in NIST SRM 610, 612 and 614 up to concentrations of at least several weight percent (which were possible to analyse due to the dynamic range of 10⁸) indicates the suitability of this technique for major, minor and trace element determinations.     

Strontium, Neodymium and Lead Isotope Analyses of NIST Glass Certified Reference Materials: SRM 610, 612, 614

The NIST glass certified reference materials, SRM 610-617, have been widely adopted by the geological community as calibration samples for a variety of in situ trace element analytical techniques. There is now an urgent requirement for similar reference materials for in situ isotopic analytical techniques. We have analysed SRM 610, 612 and 614 for their Pb, Sr and Nd isotopic compositions using thermal ionisation mass spectrometry. Large differences in isotopic composition were observed between each CRM, suggesting a significant trace element content in the initial starting material (base glass). As a result, isotopic compositions for one CRM cannot be extrapolated to another, and each must be calibrated for use independently. We present the first compilation of working values for these glasses.     

QUANTITATIVE ANALYSIS OF TRACE ELEMENTS IN GEOLOGICAL MATERIALS BY LASER ABLATION ICPMS: INSTRUMENTAL OPERATING CONDITIONS AND CALIBRATION VALUES OF NIST GLASSES

A UV laser ablation microprobe coupled to an ICPMS has been used to determine trace element concentrations in solids with a spatial resolution of 50 microns and detection limits ranging from 2 μg/g for Ni to 50 ng/g for the REE, The, and U. Experiments designed to optimize laser operating conditions show that pulse rates of 4 Hz produce a steady state signal with less inter-element fractionation per unit time than higher pulse rates (10–20 Hz). Comparisons of laser microprobe analyses of garnets and pyroxenes using the NIST 610 and 612 glasses as calibration standards, with proton microprobe, solution ICPMS, INAA and XRF data show no significant matrix effects. Laser microprobe analyses of the NIST 610 and 612 glasses have a precision and accuracy of 2–5%, and error analysis shows that counting statistics and the precision on the internal standard concentration accounts for the analytical uncertainty. The NIST glasses appear to be useful calibration materials for trace element analysis of geological materials by laser microprobe.     

Niobium and Tantalum Concentrations in NIST SRM 610 Revisited

Niobium and Ta concentrations in MPI‐DING and USGS (BCR‐2G, BHVO‐2G, BIR‐1G) silicate rock glasses and the NIST SRM 610–614 synthetic soda‐lime glasses were determined by 193 nm ArF excimer laser ablation and quadrupole ICP‐MS. Measured Nb and Ta values of MPI‐DING glasses were found to be consistently lower than the recommended values by about 15% and 25%, respectively, if calibration was undertaken using commonly accepted values of NIST SRM 610 given by Pearce et al. Analytical precision, as given by the 1 s relative standard deviation (% RSD) was less than 10% for Nb and Ta at concentrations higher than 0.1 μg g^?1. A significant negative correlation was found between logarithmic concentration and logarithmic RSD, with correlation coefficients of ‐0.94 for Nb and ‐0.96 for Ta. This trend indicates that the analytical precision follows counting statistics and thus most of the measurement uncertainty was analytical in origin and not due to chemical heterogeneities. Large differences between measured and expected Nb and Ta in glasses GOR128‐G and GOR132‐G are likely to have been caused by the high RSDs associated with their very low concentrations. However, this cannot explain the large differences between measured and expected Nb and Ta in other MPI‐DING glasses, since the differences are normally higher than RSD by a factor of 3. Count rates for Nb and Ta, normalised to Ca sensitivity, for the MPI‐DING, USGS and NIST SRM 612–614 glasses were used to construct calibration curves for determining NIST SRM 610 concentrations at crater diameters ranging from 16 (im to 60 μm. The excellent correlation between the Nb/Ca_1μgg‐1 signal (Nb represents the Nb signal intensity; Ca_{1μg g‐1} represents the Ca sensitivity) and Nb concentration, and between the Ta/Ca_{1μg g‐1} signal (where Ta represents the Ta signal intensity; Ca_{1μg g‐1} represents the Ca sensitivity) and Ta concentration (R²= 0.9992–1.00) in the various glass matrices suggests that matrix‐dependent fractionation for Nb, Ta and Ca was insignificant under the given instrumental conditions. The results confirm that calibration reference values of Nb and Ta in NIST SRM 610 given by Pearce et al. are about 16% and 28% lower, respectively. We thus propose a revision of the preferred value for Nb from 419.4 ± 57.6 μg g^?1 to 485 ± 5 μg g^?1 (1 s) and for Ta from 376.6 ± 77.6 μg g^?1 to 482 ± 4 μg g^?1 (Is) in NIST SRM 610. Using these revised values for external calibration, most of the determined average values of MPI‐DING, USGS and NIST SRM 612–614 reference glasses agree within 3% with the calculated means of reported reference values. Bulk analysis of NIST SRM 610 by standard additions using membrane desolvation ICP‐MS gave Nb = 479 ± 6 μg g^?1 (1 s) and Ta = 468 ± 7 μg g^?1 (1 s), which agree with the above revised values within 3%.     

The F,Cl, Br and I Contents of Reference Glasses BHVO‐2G,BIR‐1G,BCR‐2G,GSD‐1G,GSE‐1G,NIST SRM 610 and NIST SRM 612

Halogen contents for the widely distributed reference glasses BHVO‐2G, BIR‐1G, BCR‐2G, GSD‐1G, GSE‐1G, NIST SRM 610 and NIST SRM 612 were investigated by pyrohydrolysis combined with ion chromatography, total reflection X‐ray fluorescence analysis, instrumental neutron activation analysis, the noble gas method, electron probe microanalysis and laser ablation‐inductively coupled plasma‐mass spectrometry. Glasses BHVO‐2G, GSD‐1G and GSE‐1G have halogen contents that can be reproduced at the 15% level by all bulk techniques and cover a significant range in halogen mass fractions for F (~ 20–300 μg g^?1), Cl (~ 70–1220 μg g^?1) and Br (~ 0.2–285 μg g^?1) and I (~ 9–3560 ng g^?1). The BIR‐1G glass has low F (< 15 μg g^?1), Cl (~ 20 μg g^?1), Br (15 ng g^?1) and I (3 ng g^?1). The halogen contents for the silica‐rich NIST SRM 610 and 612 glasses were poorly reproduced by the different techniques. The relatively high Cl, Br and I abundances in glasses GSD‐1G and GSE‐1G mean that these glasses are well suited for calibrating spatially resolved micro‐analytical studies on silicate glasses, melt and fluid inclusions. Combined EPMA and laser ablation‐inductively coupled plasma‐mass spectrometry data for glass GSE‐1G demonstrate homogeneity at the 10% level for Cl and Br.     

Isotope Dilution MC-ICP-MS Rare Earth Element Analysis of Geochemical Reference Materials NIST SRM 610, NIST SRM 612, NIST SRM 614, BHVO-2G, BHVO-2, BCR-2G, JB-2, WS-E, W-2, AGV-1 and AGV-2

We present data for the concentrations of eleven rare earth elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Er, Yb, Lu) in eleven international geochemical reference materials obtained by isotope dilution multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS). We have analysed both rock powders and synthetic silicate glasses, and the latter provide precise data to support the use of these as reference materials for in situ trace element determination techniques. Our data also provide precise measurements of the abundance of mono-isotopic Pr in both glasses and powders, which allows more accurate constraints on the anomalous redox-related behaviour of Ce during geochemical processes. All materials were analysed in replicate providing data that typically reproduce to better than one percent. Sm/Nd ratios in all these materials also reproduce to better than 0.2% and are accurate to < 0.2% and can thus be used as calibrants for Sm-Nd geochronology. Our analyses agree well with existing data on these reference materials. In particular, for NIST SRM 610, USGS BHVO-2, AGV-1 and AGV-2, our measured REE abundances are typically within < 2% (and mostly 1%) of REE concentrations previously determined by isotope dilution analysis and thermal ionisation mass spectrometry, consistent with the higher degree of precision and accuracy obtained from isotope dilution techniques. Close agreement of results between basaltic glass reference materials USGS BHVO-2G and BCR-2G and the BHVO-2 and BCR-2 powders from which they were created suggests that little fractionation, concentration or dilution of REE contents occurred during glass manufacture.     

δ98/95Mo values and Molybdenum Concentration Data for NIST SRM 610, 612 and 3134: Towards a Common Protocol for Reporting Mo Data

Molybdenum concentration and δ^98/95Mo values for NIST SRM 610 and 612 (solid glass), NIST SRM 3134 (lot 891307; liquid) and IAPSO seawater reference material are presented based on comparative measurements by MC‐ICP‐MS performed in laboratories at the Universities of Bern and Oxford. NIST SRM 3134 and NIST SRM 610 and 612 were found to have identical and homogeneous ⁹⁸Mo/⁹⁵Mo ratios at a test portion mass of 0.02 g. We suggest, therefore, that NIST SRM 3134 should be used as reference for the δ–Mo notation and to employ NIST SRM 610 or 612 as solid silicate secondary measurement standards, in the absence of an isotopically homogeneous solid geological reference material for Mo. The δ^98/95Mo_{JMC Bern} composition (Johnson Matthey ICP standard solution, lot 602332B as reference) of NIST SRM 3134 was 0.25 ± 0.09‰ (2s). Based on five new values, we determined more precisely the mean open ocean δ^98/95Mo_{SRM 3134} value of 2.09 ± 0.07‰, which equals the value of δ^98/95Mo_{JMC Bern} of 2.34 ± 0.07‰. We also refined the Mo concentration data for NIST SRM 610 to 412 ± 9 μg g^?1 (2s) and NIST SRM 612 to 6.4 ± 0.7 μg g^?1 by isotope dilution. We propose these concentration data as new working values, which allow for more accurate in situ Mo determination using laser ablation ICP‐MS or SIMS.     

MAJOR AND TRACE ELEMENT DETERMINATIONS ON NIST GLASS STANDARD REFERENCE MATERIALS 611, 612, 614 AND 1834 BY INDUCTIVELY COUPLED PLASMA-MASS SPECTROMETRY

We report on the major and trace element composition and homogeneity of NIST (National Institute of Standards and Technology) glass standard reference materials 611, 612, 614, and 1834 for use as microanalytical trace element standards in laser ablation-inductively coupled plasma-mass spectrometry. The four analyzed NIST glasses were not designed as microanalytical standards, but their availability and careful preparation made them obvious candidates. Our data indicate that NIST 1834 is inhomogeneous on a scale of 100 mg with respect to several trace elements. Within analytical uncertainty, NIST 611, 612, and 614 are apparently homogeneous.     

Compositional Heterogeneity in NIST SRM 610-617 Glasses

Extensive compositional heterogeneity is shown to affect at least twenty four of the doped trace elements in the NIST SRM 610-617 glasses.
Compositional profiling and mapping using laser ablation ICP-MS reveals that all NIST SRM 610-617 wafers examined here contain domains that are significantly depleted in Ag, As, Au, B, Bi, Cd, Cr, Cs, Mo, Pb, Re, (Rh), Sb, Se, Te, Tl and W, and antithetically enriched in Cu (and Pt), with large enrichments in Cd, Fe and Mn also being encountered in some cases. These domains are visible in doubly polished wafers by unaided visual inspection and by transmitted light and schlieren microscopy. They occur in close proximity to the wafer perimeters and also as stretched and complexly folded forms within wafer interiors. The chemical and optical properties of these heterogeneous domains are consistent with those of compositional cords, a phenomenon of glass manufacture where glass bulk composition and physical properties are modified by loss of volatile components from the molten glass surface. The NIST SRM 610-617 glasses may be considered reliable reference materials for microanalysis of only between one half and two thirds of the trace elements with which they were doped, including Be, Mg, Sr, Ba, Sc, Y, REE, V, Zr, Hf, Nb, Ta, Th, U, Ga, In, Sn, Co, Ni and Zn. These elements show no evidence of significant heterogeneity, indicating that the original glass constituents and possible residues remaining in the furnace from preceding glass batch fusions were well homogenised during manufacture.     

Chemical Characterisation of NIST Silicate Glass Certified Reference Material SRM 610 by ICP-MS, TIMS, LIMS, SSMS, INAA, AAS and PIXE

National Institute of Science and Technology (NIST) silicate glass SRM 610 is widely used as a certified reference material for various micro-analytical techniques such as SIMS or laser ablation ICP-MS. SRM 610 has been nominally doped with sixty one trace elements at the 500 μg g⁻¹ level, but certified concentration data exist for only a few of these elements. This study reports concentration data for fifty nine trace elements obtained by ICP-MS, SSMS, LIMS, TIMS, INAA, AAS, and PIXE analyses of two different SRM 610 wafers. Most elements fall within a 10% band around a median value of about 440 μg g⁻¹. The REE concentrations are shown to be constant to 3% (1 σ), thus emphasizing the value of SRM 610 as a reference material for REE analyses.
Comparison of our values with published data suggests that different SRM 610 wafers are, within errors, chemically identical for most elements. Exceptions to this general rule appear to be restricted to elements which were partly lost during the production of the glass, e.g. Ag and Br. On the basis of six independent determinations of Rb concentrations, which are systematically lower by a few percent than the reported NIST value, we argue that the certified Rb concentration may not be representative for all distributed SRM 610 wafers.     

Evaluation of Major to Ultra Trace Element Bulk Rock Chemical Analysis of Nanoparticulate Pressed Powder Pellets by LA‐ICP‐MS

An efficient, clean procedure for the measurement of element mass fractions in bulk rock nanoparticulate pressed powder pellets (PPPs) by 193 nm laser ablation ICP‐MS is presented. Samples were pulverised by wet milling and pelletised with microcrystalline cellulose as a binder, allowing non‐cohesive materials such as quartz or ceramics to be processed. The LA‐ICP‐MS PPP analytical procedure was optimised and evaluated using six different geological reference materials (JP‐1, UB‐N, BCR‐2, GSP‐2, OKUM and MUH‐1), with rigorous procedural blank quantification employing synthetic quartz. Measurement trueness of the procedure was equivalent to that achieved by solution ICP‐MS and LA‐ICP‐MS analysis of glass. The measurement repeatability was as low as 0.5–2% (1s, n = 6) and, accordingly, PPP homogeneity could be demonstrated. Calibration based on the reference glasses NIST SRM 610, NIST SRM 612, BCR‐2G and GSD‐1G revealed matrix effects for glass and PPP measurement with NIST SRM 61×; using basalt glasses eliminated this problem. Most significantly, trace elements not commonly measured (flux elements Li, B; chalcophile elements As, Sb, Tl, In, Bi) could be quantified. The PPP‐LA‐ICP‐MS method overcomes common problems and limitations in analytical geochemistry and thus represents an efficient and accurate alternative for bulk rock analysis.     

Preparation of a Synthetic Titanite Glass Calibration Material for In Situ Microanalysis by Direct Fusion in Graphite Electrodes: A Preliminary Characterisation by EPMA and LA-ICP-MS

This paper describes a technique for the preparation of a titanite (CaTiSiO₅) glass calibration material for use in in situ microanalysis of major, minor, and trace elements in geological materials. The starting composition was a titanite matrix doped with minor and trace elements at ∼ 200 μg g^-1. The elements Sc, Y, REEs, Th and U were added in the form of nitrates in solution, and the elements V, Cr, Mn, Fe, Co, Ni, Zr, Nb, Hf and W were added as solid oxides. The synthetic titanite glass was produced by direct fusion by resistance heating in graphite electrodes at 1600-1700 °C, and quenched in air. Backscattered electron images indicate good homogeneity, with no signs of separate phases or vesicles, and analysis of the major elements Ca, Ti and Si by electron microprobe showed relative standard deviations between 0.5 and 0.7%, based on six independent measurements. Deviations from nominal concentrations for Ca, Si and Ti were measured to -1.2, -3.3 and -0.8%, respectively. The homogeneity of the trace elements in the glass was assessed by LA-ICP-MS analyses, using NIST SRM 610, 612 and 616 as external calibrators, and Ca as the internal standard element. Determinations were made both with a quadrupole mass spectrometer and a sector field instrument, and both raster and spot modes of analysis were used. For the majority of doped elements, precision was better than 10%, and relative deviations from nominal values were, with few exceptions, between 5 and 10%.     

Determination of Lithium, Beryllium and Boron at Trace Levels by Laser Ablation-Inductively Coupled Plasma-Sector Field Mass Spectrometry

The analytical capabilities of laser ablation (LA)-ICP-MS in determining Li, Be and B at trace levels in geological samples have been tested on a series of glass reference materials and natural samples. The LA-ICP-MS instrument used consisted of a sector-field ICP-MS coupled with a laser ablation microprobe operating at either 266 or 213 nm wavelength. Reference glasses from NIST (SRM 612, 614 and 616) and MPI-DING (KL2-G, ML3B-G, StHs6/80-G, GOR128-G, GOR132-G, T1-G and ATHO-G) were selected to develop the analytical method and to assess the best instrumental configuration. A series of calcic amphiboles with different Li, Be and B concentrations were also analysed using both LA-ICP-MS and SIMS to test the applicability of the method to natural minerals. Results indicated that with a spot size of 40 μm the agreement between measured and reference values of Li, Be and B is generally better than 10% for NIST SRM 612 and 20% for NIST SRM 614. Average reproducibility at the 2s level was 10% for Li, 20% for Be and 15% for B. Limits of detection were approximately 100 ng g^-1 for Be and B and 200 ng g^-1 for Li. These results were confirmed by analyses carried out on natural amphiboles and compared well in terms of precision and accuracy with those commonly achieved by SIMS.