Laser Ablation and Solution ICP-MS Determination of Rare Earth Elements in USGS BIR-1G, BHVO-2G and BCR-2G Glass Reference Materials

Data are reported for rare earth elements (REE) in three geological glass reference materials (BIR-1G, BHVO-2G and BCR-2G) using a UV (266 nm) laser ablation ICP-MS system and the classical (HF-HClO₄) acid decomposition method, followed by conventional nebulisation ICP-MS. External calibration of laser ablation analyses was performed using NIST SRM reference materials with internal standardisation using ²⁹Si and ⁴⁴Ca. Replicate analyses of reference basaltic glasses yielded an analytical precision of 1-5% (RSD) for all the elements by solution ICP-MS and 1-8% (RSD) by laser ablation ICP-MS. The relative differences between the REE concentrations measured by solution and laser ablation ICP-MS compared with the reference values were generally less than 11 % for most elements. The largest deviations occurred for La determined by solution ICP-MS in BIR-1G. The results of both solution and laser ablation ICP-MS agreed well, generally better than 7%, with the exception of La, Pr and Sm in BIR-1G. The measured REE laser ablation data for BIR-1G, BHVO-2G and BCR-2G agreed with the previously published data on these basaltic reference glasses, within a range of 0-10% for most elements. No significant influences were observed for the predicted spectral interferences on some REE isotopes in the analysis of basaltic glasses.     

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.     

Application of High Spatial Resolution Laser Ablation ICP-MS to Crystal-Melt Trace Element Partition Coefficient Determination

In this contribution we evaluate the capabilities of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) using a 12 μm spot size. Precision, accuracy and detection limits were assessed on the USGS BCR-2G reference material. We demonstrate that the 12 μm LA-ICP-MS analyses of experimentally-grown amphibole and garnet are in excellent agreement with secondary ion mass spectrometry (SIMS) trace element determinations on the same crystals. The 12 μm spot size configuration was subsequently used to determine trace element crystal-melt partition coefficients (D_c/m) for a wide range of trace elements in amphibole in equilibrium with a basanitic melt. The following strategy to determine accurately and evaluate D_c/m is proposed. One or more major elements determined previously by electron probe microanalysis (EPMA) was used to ensure consistency between EPMA and the composition of the aerosol produced by the laser ablation. Measured D_c/m values were successively evaluated using the lattice strain model. The use of this strategy significantly improved the precision and accuracy of D_c/m determination when a LA-ICP-MS configuration with a high spatial resolution was employed.     

Results for Rarely Determined Elements in MPI-DING, USGS and NIST SRM Glasses Using Laser Ablation ICP-MS

New analytical results are reported for rarely determined elements Be, B, Ge, As, Mo, Rh, Pd, Ag, Cd, In, Sn, Sb, W, Re, Ir, Pt, Au, Tl and Bi in MPI‐DING and USGS (BCR‐2G, BHVO‐2G, BIR‐1G) silicate glasses and the NIST SRM 610‐614 synthetic soda‐lime glasses using 193 nm ArF excimer laser ablation and quadrupole ICP‐MS. The method used involved external calibration against GOR132‐G for Ir and NIST SRM 610 for other elements, internal standardisation using Ca, and ablation with a crater diameter of 160 μm and a pulsed laser repetition rate of 10 Hz. Small amounts of nitrogen (5 ml min^?1) were added to the central channel gas of the plasma to improve the limits of detection for most of these elements by a factor of 1.2–2.5 and to reduce the oxide interference level to 0.02% (ThO⁺/Th⁺). Under these conditions, the LODs for most of these rarely determined elements were within the range 0.1 to 10 ng g^?1. The operating conditions that were required to minimise ICP‐induced fractionation (U⁺/Th⁺≈ 1) in the mode without nitrogen were accompanied by a 50–60% reduction in sensitivity for elements such as Ca, Au and Pt. In contrast, ICP‐induced fractionation could be minimised (U⁺/Th⁺≈ 1) with no loss of analyte sensitivity in the nitrogen mode. Interferences of CuAr⁺, ZnAr⁺, Cd⁺, Pb²⁺ and Sn⁺ on Pd⁺, Rh⁺, Cd⁺ and In⁺ were corrected. Oxide interferences were not considered due to their lower production rate. Analytical precision, as given by one relative standard deviation (% RSD) was less than 15% for most of the elements present at concentrations greater than 0.1 μg g^?1. A significant negative correlation was found between logarithmic concentration and logarithmic RSD, with a correlation coefficient of ?0.76. This trend indicates that possible chemical heterogeneities for most of these elements are smaller than the analytical uncertainty. Our results for Be, B, Ge, Sb and W are generally in good agreement with their reference values. In contrast, other elements in many of the reference glasses have only information values, upper limits or even no values, which restrict any detailed evaluation of the accuracy of the determined values. However, concentrations from multiple isotopes of one element analysed in this study showed excellent agreement, which guarantee the quality of our data to a certain extent.     

等离子体质谱法测定天然水中痕量元素

本文利用ICP-MS分析技术检出限低,可同时测定多元素,以及溶液进样等特点,建立了天然水中多种痕量元素分析的有效方法,研究了整个测定质量范围内的背景、干扰及其克服方法,讨论了水中Na、Mg、Ca等元素产生的基体效应对被测元素的影响。对含盐量较低的天然水样,可直接测定的痕量元素达50余种,测定限为0.x—xμg/L。高盐水样如海水、卤水等的测定,本文选择共沉淀法,以Fe(OH)_3为捕集剂,使被测元素与大量的碱金属、碱土金属基体分离。分离后可测40种痕量元素,测定限为0.0x—0.xμg/L。     

Laser Ablation ICP-MS Analysis of Geological Materials Prepared as Lithium Borate Glasses

A simple, rapid and precise method is described for determining trace elements by laser ablation (LA)-ICP-MS analysis in bulk geological materials that have been prepared as lithium borate glasses following standard procedures for XRF analysis. This approach reliably achieves complete sample digestion and provides for complementary XRF and LA-ICP-MS analysis of a full suite of major and trace elements from a single sample preparation. Highly precise analysis is enabled by rastering an ArF excimer laser (λ= 193nm) across fused samples to deliver a constant sample yield to the mass spectrometer without inter-element fractionation effects during each analysis. Capabilities of the method are demonstrated by determination of twenty five trace elements (Sc, Ti, V, Ga, Rb, Sr, Y, Zr, Nb, Cs, Ba, REE, Hf, Ta, Pb, Th and U) in a diverse range of geological reference materials that includes peridotites, basalts, granites, metamorphic rocks and sediments. More than 90% of determinations are indistinguishable from published reference values at the 95% confidence level. Systematic bias greater than 5% is observed for only a handful of elements (Zr, Nb and U) and may be attributed in part to inaccurate calibration values used for the NIST SRM 612 glass in the case of Zr and Nb. Detection limits for several elements, most notably La, are compromised at ultra-trace levels by impurities in the lithium borate flux but can be corrected for by subtracting appropriate procedural blanks. Reliable Pb analysis has proved problematic due to variable degrees of contamination introduced during sample polishing prior to analysis and from Pt-crucibles previously used to fuse Pb-rich samples. Scope exists for extending the method to include internal standard element/isotope spiking, particularly where integrated XRF analysis is not available to characterise major and trace elements in the fused lithium borate glasses prior to LA-ICP-MS analysis.     

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.     

激光剥蚀电感耦合等离子体质谱法测定碳酸盐矿物中元素组成

碳酸盐中微量元素信息可为探究古环境、古气候演化、壳幔相互作用以及成岩成矿等重要地质作用过程提供关键约束,其微量元素含量的准确测定一直备受学者关注。激光剥蚀电感耦合等离子体质谱（LA-ICP-MS）可提供碳酸盐矿物中微量元素含量的精细信息,而常规激光测试方法严重制约着碳酸盐矿物微量元素分析的空间分辨率和低含量元素的检测能力。相比于常规剥蚀池条件时的低频率分析,本研究通过采用气溶胶局部提取快速清洗剥蚀池结合高频率激光剥蚀的方式,快速提升激光微区分析瞬时信号强度,有效地提升峰形信号灵敏度（约13倍）,碳酸盐激光微区元素检出限降低5～10倍。在此激光分析模式下,分别采用纳秒和飞秒激光剥蚀联用四极杆等离子体质谱仪（LA-Q-ICP-MS）,以NIST610玻璃为外标,Ca为内标开展了较小激光剥蚀束斑（32μm）条件下碳酸盐矿物中微量元素（亲石元素、亲铁和亲硫元素）分析。结果表明,纳秒和飞秒激光分析碳酸盐矿物标样CGSP-A、CGSP-B、CGSP-C、CGSP-D和MACS-3获得的亲石元素（如Sc、Sr、Y、Ba、La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb和Th等）测试值与推荐值在误差范围内一致;而亲铁和亲硫元素（如Ni、Cu、Zn、As、Cd、Sn、Sb和Pb）测试结果则存在较大偏差（大于20%）,这可能与本研究选用的高频激光剥蚀和较小剥蚀束斑（32µm）造成显著的“Downhole”分馏效应有关。本研究通过研制新型激光剥蚀池,改变激光剥蚀方式,即采用气溶胶局部提取剥蚀池和高频率剥蚀方法可有效地提升碳酸盐矿物微量元素（如亲石元素）分析的空间分辨率和低含量元素检测能力,有利于促进碳酸盐矿物在地质环境等领域的广泛应用。     

Concentrations of Trace Elements in Carbonate Reference Materials Coral JCp-1 and Giant Clam JCt-1 by Inductively Coupled Plasma-Mass Spectrometry

Trace elements in the Geological Survey of Japan carbonate reference materials Coral JCp-1 and Giant Clam JCt-1 were determined by inductively coupled plasma-mass spectrometry after digestion with 2% v/v HNO₃. A standard addition method was adopted in this determination in order to neutralise the Ca matrix effect. In addition, Sc, Y, In and Bi were used as internal standards to control the matrix effect and correct instrumental drift. Of the eighteen elements measured in JCp-1, precisions for fourteen elements, including Cu, Cd and Ba, were better than 10% RSD and concentrations ranged from 0.002 μg g^-1 (Cs) to 8.02 μg g^-1 (Ba). The concentrations of measured trace elements in JCt-1, except for Cu, were lower than those in JCp-1. Precisions for all elements with concentrations higher than 0.04 μg g^-1 in JCt-1 were also better than 10% RSD and concentrations were found to be between 0.001 μg g^-1 (Cs) and 4.84 μg g^-1 (Ba). The concentrations of more than fifteen trace elements in the aragonite reference materials are reported here for the first time. Both reference materials are suitable for use in geochemical studies of environmental reconstruction based upon biogenic carbonate materials.     

Determination of REE, Y, Nb, Zr, Hf, Ta, Th and U in Geological Reference Materials LSHC-1 and Amf-1 by Solution and Laser Ablation ICP-MS

This paper presents data on REE and Y, Nb, Zr, Hf, Ta, Th and U abundances for two candidate reference materials (RMs), spinel lherzolite LSHC-1 and amphibole Amf-1, being currently developed at the Institute of Geochemistry SB RAS, Irkutsk. To determine the contents of these elements inductively coupled plasma-mass spectrometry was applied with: (i) solution nebulisation (solution ICP-MS) and (ii) laser ablation (LA-ICP-MS) of fused glass disks. The precision of results obtained by both techniques was better than 6% RSD for most elements. Accuracy was assessed by using the geochemical RMs JB-2, JGb-1 (GSJ) and MAG-1 (USGS). The trace element results by solution ICP-MS for JGb-1 and JB-2 agree with reference values presented by Imai et al. (1995, this Journal) within 1–10%. Significant differences were found for Nb and Ta determinations. The accuracy of LA-ICP-MS results evaluated by RM MAG-1 was within 4%, except for Eu (about 10%). The analytical results obtained for LSHC-1 and Amf-1 by solution ICP-MS and LA-ICP-MS were in good agreement with each other and with INAA and XRF data presented for the certification of these RMs. They can be considered as the indicative values for assigning certified values to the above-mentioned RMs.     

Application of Laser Ablation ICP-MS to U-Th-Pb Dating of Monazite

Recent advances in laser ablation ICP-MS techniques allow accurate U-Th-Pb age dating of monazites that are as young as several tens of million years to a precision better than 2%. Accuracy of the age determinations has been improved by true real-time mass bias correction via nebulisation of a solution containing enriched ²³³U and natural Tl isotopes. The Tl-U tracer solution eliminates possible effects of variable sample matrices on the precision and accuracy of measured isotopic ratios. Mass bias corrections based on measured ²⁰⁵Tl/²³³U ratios in the tracer solution allow direct measurement of ²³⁵U in monazite. Combined with high-sensitivity laser ablation ICP-MS measurements, direct measurement of ²³⁵U particularly improves the precision of U-Pb dating of young monazites. Correction for laser-induced Pb/U and Pb/Th elemental fractionation is based on a mathematical treatment of time resolved count-rate data that is independent of laser ablation characteristics, does not require external standardisation and allows variable laser pit size or raster patterns for each measurement. The new procedures make the LA ICP-MS technique more flexible for in situ U-Th-Pb analysis.     

Platinum-Group Elements and Gold Determination in NiS Fire Assay Buttons by UV Laser Ablation ICP-MS

The direct analysis of nickel sulfide fire assay buttons by UV laser ablation ICP-MS was used to determine the platinum-group elements and gold in the following reference materials: UMT-1, WPR-1, WMG-1, GPt-4, GPt-6 and CHR-Bkg. The instrument was calibrated with buttons prepared using quartz doped with the appropriate standard solutions. Analytical precision (RSD) was generally better than 10%, although occasional higher RSDs may infer local heterogeneities within nickel sulfide buttons. Good or excellent agreement was observed between analysed and reference material values except Rh in UMT-1 and WMG-1, which suffered an interference from copper. Detection limits calculated as 10 s quantitation limits were Au (1.7 ng g⁻¹), Pd (3.3 ng g⁻¹), Pt (8.3 ng g⁻¹), Os (1.3 ng g⁻¹), Rh (1 ng g⁻¹), Ru (5 ng g⁻¹) and Ir (0.7 ng g⁻¹).     

Determination of Trace Elements in Twenty Six Chinese Geochemistry Reference Materials by Inductively Coupled Plasma-Mass Spectrometry

We report new data for thirty seven elements determined in twenty six Chinese geochemistry reference materials using inductively coupled plasma-mass spectrometry and a reliable and simple dissolution technique. One hundred milligrams of sample were digested with 1 ml of HF and 0.5 ml of HNO₃ in PTFE-lined stainless steel bombs heated to 200 °C for 12 hours. Insoluble residues were dissolved using 6 ml of 40% v/v HNO₃ heated to 140 C for 3 hours. Analytical calibration was accomplished using aqueous standard solutions. Rhodium was used as an internal standard to correct for matrix effects and instrument drift. Precisions were typically better than 5% RSD. Most of the data presented here agree well with the published certified values. For the elements Zr, Hf and most other trace elements, the measured values were less than 10% in error when compared to certified values.     

Trace Element Analysis of NIST SRM 614 and 616 Glass Reference Materials by Laser Ablation Microprobe-Inductively Coupled Plasma-Mass Spectrometry

Fifty elements in NIST SRM 614 and 616 glass reference materials were determined by laser ablation microprobe-inductively coupled plasma-mass spectrometry (LAM-ICP-MS). The values determined for NIST SRM 614 agreed well with the NIST-certified and information values (mean relative difference ± 3.6%), except for B, Sc and Sb. The values determined for NIST SRM 616 agreed with the NIST-certified and information values within a mean relative difference of ± 1.5%, except for B, Sc and Ga. In addition, at an 80 μm sampling scale, NIST SRM 614 and 616 glass discs were homogeneous for trace elements within the observed precisions of 5 and 15% (mean), respectively. Detection limits were in the range 0.01 - 0.3 μg g⁻¹ for elements of lower mass numbers (amu < 80) and 1 - 10 ng g⁻¹ for heavy elements (amu > 80). Detection at the sub ng g⁻¹ level is possible for most of the heavy elements by using an ablation pit size larger than 10 0 μm.     

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.     

A Protocol for the Determination of the Rare Earth Elements at Picomole Level in Rocks by ICP-MS: Results on Geological Reference Materials USGS PCC-1 and DTS-1

Rare earth element analyses are widely used in geology, environmental science and archaeology. Over the past decade inductively coupled plasma-mass spectrometry has become an important source of rare earth data on geological material. However, ICP-MS analysis of rock samples without pre-concentration can be problematic because of complex sample matrices that can generate significant molecular isobaric interferences on rare earth peaks and which need to be corrected. Such problems are exacerbated for ultramafic rocks because the low levels of rare earth elements demand more concentrated solutions in order to maintain signals above background levels. These high solid loads result in intra-run changes in instrument sensitivity which need to be monitored. Pre-concentration chemistries have been developed in order to avoid high solid loads but these are time-consuming and must offer quantitative recoveries or use a yield tracer. Here, we describe an alternative method for rare earth element analysis by ICP-MS, which involves no pre-concentration and is, therefore, able to deliver data rapidly. Our approach is to apply an external correction procedure, based on the analysis of a reference material closely matched in composition to the unknown samples, which allows correction for both interferences and variations in instrument sensitivity. Testing this method, we obtained accurate rare earth element results for basaltic rocks with a precision of about 2% (1s). We demonstrate that the method is also applicable to ultramafic rocks with abundances at ultra-trace (ng g⁻¹) level and present data for twelve separate dissolutions of the peridotite USGS PCC-1 and four separate dissolutions of the dunite DTS-1 reference materials. The repeatability of the data is between 3% and 9% (1s).     

Determination of Trace Elements in the Quartz Reference Material UNS-SpS and in Natural Quartz Samples by ICP-MS

A procedure for the digestion and analysis of quartz samples was developed to measure trace element concentrations in natural quartz. The certified glass sand reference material UNS-SpS was chosen to assess the precision, accuracy and detection limit of the analytical method. Quartz was digested with HF/HNO₃ in a closed glassy carbon vessel and analysed by means of quadrupole ICP-MS with external calibration. Analyte concentrations of the sand UNS-SpS were compared with certified and other values from the literature. The abundances of a number of elements (Pr, Gd, Ho and Er) in the reference material are reported here for the first time. The procedure was then applied to three quartz samples from different geological settings to show that trace element data by ICP-MS can distinguish the origin of the sample.     

Determination of major and trace elements in sphalerite using laser ablation double focusing sector field ICP-MS

The analytical performance of laser ablation (LA) for the determination of Co, Fe, Cd, Ag, Mn, Cu and S in sphalerite was evaluated using double focusing sector field inductively coupled plasma mass spectrometry (ICP-SFMS). Samples were collected from Zinkgruvan, situated in the south central Sweden. The use of Zn for internal standardisation, together with correction for FeS impurities in sphalerite, allows straightforward quantification without using external methods for the determination of the actual Zn content. LA–ICP-SFMS results were compared with data obtained by conventional pneumatic nebulisation introduction of sample solutions following acid digestion. Good agreement between the two methods was obtained for homogeneously distributed elements. For the majority of the elements under consideration, LA–ICP-SFMS precision was better than 10% RSD.     

Incorporation of U,Pb and Rare Earth Elements in Calcite through Crystallisation from Amorphous Calcium Carbonate: Simple Preparation of Reference Materials for Microanalysis

Uncertainty for elemental and isotopic measurements in calcite by LA‐ICP‐MS is largely controlled by the homogeneity of the reference materials (RMs) used for calibration and validation. In order to produce calcite RMs with homogeneous elemental and isotopic compositions, we incorporated elements including U, Pb and rare earth elements into calcite through heat‐ and pressure‐induced crystallisation from amorphous calcium carbonate that was precipitated from element‐doped reagent solution. X‐ray absorption spectra showed that U was present as U(VI) in the synthesised calcite, probably with a different local structure from that of aqueous uranyl ions. The uptake rate of U by our calcite was higher in comparison with synthetic calcite of previous studies. Variations of element mass fractions in the calcite were better than 12% 2RSD, mostly within 7%. The ²⁰⁷Pb/²⁰⁶Pb ratio in the calcite showed < 1% variations, while the ²³⁸U/²⁰⁶Pb ratio showed 3–24% variations depending on element mass fractions. Using the synthetic calcite as primary RMs, we could date a natural calcite RM, WC‐1, with analytical uncertainty as low as < 3%. The method presented can be useful to produce calcite with controlled and homogeneous element mass fractions and is a promising alternative to natural calcite RMs for U‐Pb geochronology.