Precise and accurate isotopic measurements using multiple-collector ICPMS

New techniques of isotopic measurements by a new generation of mass spectrometers equipped with an inductively-coupled-plasma source, a magnetic mass filter, and multiple collection (MC-ICPMS) are quickly developing. These techniques are valuable because of (1) the ability of ICP sources to ionize virtually every element in the periodic table, and (2) the large sample throughout. However, because of the complex trajectories of multiple ion beams produced in the plasma source whether from the same or different elements, the acquisition of precise and accurate isotopic data with this type of instrument still requires a good understanding of instrumental fractionation processes, both mass-dependent and mass-independent. Although physical processes responsible for the instrumental mass bias are still to be understood more fully, we here present a theoretical framework that allows for most of the analytical limitations to high precision and accuracy to be overcome. After a presentation of unifying phenomenological theory for mass-dependent fractionation in mass spectrometers, we show how this theory accounts for the techniques of standard bracketing and of isotopic normalization by a ratio of either the same or a different element, such as the use of Tl to correct mass bias on Pb. Accuracy is discussed with reference to the concept of cup efficiencies. Although these can be simply calibrated by analyzing standards, we derive a straightforward, very general method to calculate accurate isotopic ratios from dynamic measurements. In this study, we successfully applied the dynamic method to Nd and Pb as examples. We confirm that the assumption of identical mass bias for neighboring elements (notably Pb and Tl, and Yb and Lu) is both unnecessary and incorrect. We further discuss the dangers of straightforward standard-sample bracketing when chemical purification of the element to be analyzed is imperfect. Pooling runs to improve precision is acceptable provided the pooled measurements are shown to be part of a single population. Second-order corrections seem to be able to improve the precision on ¹⁴³Nd/¹⁴⁴Nd measurements. Finally, after discussing a number of potential pitfalls, such as the consequence of peak shape, correlations introduced by counting statistics, and the effect of memory on double-spike methods, we describe an optimal strategy for high-precision and accurate measurements by MC-ICPMS, which involves the repetitive calibration of cup efficiencies and rigorous assessment of mass bias combined with standard-sample bracketing. We suggest that, when these simple guidelines are followed, MC-ICPMS is capable of producing isotopic data precise and accurate to better than 15 ppm.     

钼同位素比值的双稀释剂测定方法研究

本文报道了运用多接收器等离子体质谱测定Mo同位素组成的方法,测定过程中使用双稀释剂法校正仪器的质量分馏.Fisher-Mo标准溶液和双稀释剂的100Mo/97Mo使用Fisher-Pd标准溶液中的104pd/102pd标定,其他Mo同位素比值通过100Mo/97Mo标定;本文对运用双稀释剂技术进行Mo同位素测定的长期重...     

Mo稳定同位素研究进展

随着表面热离子质谱(TIMS)和多接收器电感耦合等离子体质谱(MC-ICP-MS)的广泛应用以及同位素分析方法的改进,近10年来非传统稳定同位素(Cu、Zn、Fe、Se、Mo、Cr、Hg等)的研究得到迅速发展.其中,由于Mo同位素的分馏明显受氧化还原条件的控制,使其在指示古环境及古气候的变化方面有独特的地球化学指示意义.同时,Mo同位素在指示成矿物质来源和海洋Mo循环等方面也取得较大成果.因此,Mo同位素地球化学研究已成为国际地学领域的一个前沿和热点.本文综合前人的研究成果,结合近期自己的工作,论述了Mo同位素地球化学研究领域的一些重要进展,详细介绍了Mo同位素的化学分离、提纯和质谱分析技术,并对其应用前景进行了展望.     

Iron isotopic analyses of geological reference materials on MC-ICP-MS with instrumental mass bias corrected by three independent methods

Here we report iron (Fe) isotopic data of three pure Fe solution standards (IRMM-014, GSB Fe, and NIST 3126a) 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 ⁵⁷Fe–⁵⁸Fe 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 δ⁵⁶Fe 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 (δ⁵⁶Fe?=?0.363?±?0.006, 2SE, 95% CI; and δ⁵⁷Fe?=?0.534?±?0.010, 2SE).     

Sulfur isotope measurement of sulfate and sulfide by high-resolution MC-ICP-MS

We have developed a technique for the accurate and precise determination of ³⁴S/³²S isotope ratios (δ³⁴S) in sulfur-bearing minerals using solution and laser ablation multiple-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). We have examined and determined rigorous corrections for analytical difficulties such as instrumental mass bias, unresolved isobaric interferences, blanks, and laser ablation- and matrix-induced isotopic fractionation. Use of high resolution sector-field mass spectrometry removes major isobaric interferences from O₂⁺. Standard-sample bracketing is used to correct for the instrumental mass bias of unknown samples. Background on sulfur masses arising from memory effects and residual oxygen-tailing are typically minor (< 0.2‰, within analytical error), and are mathematically removed by on-peak zero subtraction and by bracketing of samples with standards determined at the same signal intensity (within 20%). Matrix effects are significant (up to 0.7‰) for matrix compositions relevant to many natural sulfur-bearing minerals. For solution analysis, sulfur isotope compositions are best determined using purified (matrix-clean) sulfur standards and sample solutions using the chemical purification protocol we present. For in situ analysis, where the complex matrix cannot be removed prior to analysis, appropriately matrix-matching standards and samples removes matrix artifacts and yields sulfur isotope ratios consistent with conventional techniques using matrix-clean analytes. Our method enables solid samples to be calibrated against aqueous standards; a consideration that is important when certified, isotopically-homogeneous and appropriately matrix-matched solid standards do not exist. Further, bulk and in situ analyses can be performed interchangeably in a single analytical session because the instrumental setup is identical for both. We validated the robustness of our analytical method through multiple isotope analyses of a range of reference materials and have compared these with isotope ratios determined using independent techniques. Long-term reproducibility of S isotope compositions is typically 0.20‰ and 0.45‰ (2σ) for solution and laser analysis, respectively. Our method affords the opportunity to make accurate and relatively precise S isotope measurement for a wide range of sulfur-bearing materials, and is particularly appropriate for geologic samples with complex matrix and for which high-resolution in situ analysis is critical.     

Rubidium Isotope Ratios of International Geological Reference Materials

In this study we determined rubidium isotope ratios in twenty-one commonly used international geological reference materials, including igneous, sedimentary and metamorphic rocks, as well as an IAPSO seawater reference material. All δ⁸⁷Rb results were obtained relative to the NIST SRM 984 reference material. For most reference materials, Rb was purified using a single column loaded with Sr-spec resin. For reference materials containing low Rb but high mass fractions of matrix elements (such as basic rock and seawater), Rb was purified using two-column chromatography, with the first column packed with AGMP-50 resin and the second column packed with Sr-spec resin. Two methods for instrumental mass bias correction, sample-standard bracketing (SSB) mode, and the combined sample-standard bracketing and Zr internal normalisation (C-SSBIN) method, were compared for Rb isotopic measurements by multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS). The long-term reproducibility of Rb isotopic measurements using both methods was similar, better than 0.06‰ (2s, standard deviation) for NIST SRM 984. Significant Rb isotopic fractionation was observed among the reference materials, with an overall variation in δ⁸⁷Rb values of approximately 0.5‰. The δ⁸⁷Rb values of igneous rocks ranged from -0.28‰ to +0.06‰, showing a trend from heavier isotopic compositions in mafic rocks to lighter δ⁸⁷Rb values in the more evolved felsic rocks. The sedimentary and metamorphic rocks had Rb isotope ratios similar to those of igneous rocks. The δ⁸⁷Rb values of the reference materials related to low-temperature geological processes showed a wider range than those of high-temperature processes. Notably, the IAPSO seawater reference material had a δ⁸⁷Rb value of +0.14‰, which deviated from that of igneous rocks, and represents the heaviest reservoir of Rb isotopes found thus far on Earth. The comprehensive dataset presented here has the potential to serve for quality assurance purposes, and provide a framework for interlaboratory comparisons of Rb isotope ratios.     

Effective Correction of Mass Bias for Rhenium Measurements by MC-ICP-MS

The geochemistry of Re-Os and the recent use of Re as a non-traditional stable isotope both need accurate and precise quantification of ¹⁸⁷Re/¹⁸⁵Re ratios. This paper reports rhenium isotopic data obtained from the analysis of a standard solution and geological samples by MC-ICP-MS. We show that measured isotopic ratios are modified by matrix effects that cannot be accounted for by the standard solution bracketing technique. The bias resulting from measurements on a spiked (¹⁸⁵Re-enriched) sample is shown to alter the apparent Re concentration by several percent. When spiking samples and calibrators with tungsten, simultaneous measurement of tungsten and rhenium isotopes compensates for the matrix-induced modification of mass bias. Rhenium and tungsten are shown to have different fractionation factors. This may be due to the fact that the two elements fractionate in a different but systematic way, or that the reference isotopic ratios used for elemental Re and W are incoherent with one another. The consistency of fractionation through time can be used to obtain an empirical relationship between W and Re measured ratios from a standard solution to obtain a sample's fractionation-corrected ¹⁸⁷Re/¹⁸⁵Re spiked ratio on samples containing pg g⁻¹ levels of Re, even if some matrix capable of affecting mass bias remains in the final solution.     

Sr and Pb isotopic composition of five USGS glasses (BHVO-2G, BIR-1G, BCR-2G, TB-1G, NKT-1G)

Sr isotopic compositions and Rb / Sr ratios of three USGS glasses (BHVO-2G, BIR-1G, BCR-2G) are identical to those of the original USGS reference materials. NKT-1G and TB-1G give values of 0.70351 and 0.70558, respectively. Pb isotopic ratios were measured by the standard-sample bracketing technique on an MC-ICP-MS, which give results that are comparable in accuracy and reproducibility to double spike analyses. However, assessment of the reproducibility of the technique is hampered by inhomogeneous contamination of all USGS reference materials analysed. This contamination is likely to be the reason why the USGS glasses do not all have the same Pb isotopic composition as their unfused originals. Powdered glasses, distributed for characterisation of the glasses by bulk analytical techniques, do not all have the same Pb isotopic compositions as the solid glass material, and can therefore not be used for this purpose.     

多接收器电感耦合等离子体质谱法测定镉标准溶液中镉的同位素组成

建立了多接收器电感耦合等离子体质谱仪对Cd标准溶液同位素组成进行分析的实验方法。仪器的质量分馏校正采用Standard-Sample Bracketing法。实验结果用δ114/110Cd来表达。在此研究基础上,以SPEX Cd标准溶液为参考标准,对国外4种Cd标准溶液进行了测定。结果表明,实验测定的精度在0.07‰~0.13‰(δ114/110Cd),与目前文献报道的结果具有相似的精度。以最新SPEX Cd标准样品(δ114/110Cd=0)为基准,计算的δ114/110CdJMC、δ114/110CdSPEX-1、δ114/110CdBAM1012和δ114/110CdM櫣nster的值分别为0.55‰、0.56‰、-0.65‰和5.14‰,说明不同批次SPEX标准溶液的Cd同位素组成是明显不同的,最新的SPEX Cd标准溶液与SPEX-1 Cd的δ114/110Cd值存在着0.56‰的差别。将以SPEX Cd为参考标准的δ114/110CdBAM1012和δ114/110CdM櫣nster转化为以SPEX-1或JMC为参考标准后,得到的结果与文献报道的结果在误差范围内一致。     

钼同位素的MC-ICP-MS测定方法研究

本文报道了运用多接收器等离子体质谱进行Mo同位素组成测定的方法, 测定过程中的仪器质量歧视校正采用样品－标样交叉法。实验对Mo同位素测定过程中的谱峰干扰、基体效应、浓度效应、酸度效应和重现性等问题进行了详细研究。结果表明Zr的存在对Mo同位素测定不会产生影响; Sr不适合作为Mo同位素测定的元素内标; 当m(Ag)/m(Mo)≤1时, Ag的存在不会对Mo同位素测定产生影响; 当样品相对于标样的Mo浓度变化不大于50%时, Mo同位素分析不受浓度影响; 以HNO3为进样介质时, HNO3的浓度(0.1 mol/L~0.2 mol/L)对Mo同位素分析没有影响。CAGS-Mo相对于Alfa-Mo的δ100/95Mo、δ98/95Mo和δ97/95Mo分别为－0.34‰±0.10‰(2sd)、－0.22‰±0.05‰(2sd)和－0.13‰±0.08‰(2sd), 在95%的置信区间内, 该方法的外部精度不大于0.06‰/amu。     

Multiple Collector ICP-MS: Introduction to Instrumentation, Measurement Techniques and Analytical Capabilities

The technique of multiple collector ICP-MS (MC-ICP-MS) has recently attracted much attention, because it permits the precise measurement of isotope compositions for a wide range of elements. This review article discusses the particular advantages of this mass spectrometric technique and provides an overview of the instrumentation. The performance characteristics of MC-ICP-MS instruments and procedures for the correction of instrumental mass discrimination are covered. The strategies that are employed to avoid analytical artefacts from spectral interferences and matrix effects are also considered. A range of applications are then discussed, to provide an overview of the versatility of this mass spectrometric technique. The diversity of applications, which include the measurement of radiogenic and stable isotope ratios, the determination of trace element concentrations by isotope dilution and in situ isotopic measurements using a laser ablation system, highlight the great relevance of MC-ICP-MS to present and future research in various Earth science disciplines.     

Standard-sample bracketing calibration method combined with Mg as an internal standard for silicon isotopic compositions using multi-collector inductively coupled plasma mass spectrometry

Silicon isotope analysis traditionally uses a standard-sample bracketing (SSB) method that relies upon greater instrument stability than can be consistently expected. The following proposed method reduces the level of instrumental stability required for the analysis process and provides a valid solution for high-precision and accurate studies of Si isotopic compositions. Rock samples were dissolved by using alkali fusion and acidification. Silicon isotopes were purified with an ion exchange resin. Interfering peaks for isotopes were separated by using a Nu Plasma 1700 multi-collector inductively coupled plasma mass spectrometry (MS) system in high-resolution mode (M/ΔM > 8000 RP). Two magnesium isotopes (²⁵Mg and ²⁶Mg) and three silicon isotopes (²⁸Si, ²⁹Si, and ³⁰Si) were analyzed in the same data collection cycle. Mg isotopes were used as an internal standard to calibrate the mass discrimination effects in MS analysis of Si isotopes in combination with the SSB method in order to reduce the effects of MS interference and instrumental mass discrimination on the accuracy of measurements. The conventional SSB method without the Mg internal standard and the proposed SSB method with Mg calibration delivered consistent results within two standard deviations. When Mg was used as an internal standard for calibration, the analysis precision was better than 0.05 ‰ amu.     

样品量的大小对铜锌同位素测定值的影响

利用多接收电感耦合等离子体质谱法测定铜、锌同位素比值时,样品量的大小对其同位素测定值存在一定的影响。本研究中使用不同量的实验室标准溶液(CAGS-Cu、CAGS-Zn)过柱,并以该标准溶液为基准,采用标准-样品交叉法测定铜、锌同位素比值。结果表明,当铜、锌的样品量小到一定程度时,其同位素测定值偏离真值;当铜、锌的样品量足够大时,其同位素测定值趋于真值。流程本底对同位素测定值的影响可忽略不计,同时也不存在同质异位素干扰,说明这一现象极可能来自所用试剂和离子交换树脂的杂质组分产生的基质效应。在本文报道的实验条件下,当铜的样品量≥4μg、锌的样品量≥1μg时才能够确保铜、锌同位素测定结果的准确性。这一现象是否在其他同位素体系的测试过程存在,是个值得注意的问题。     

Determination of the isotopic composition of molybdenum in the bottom sediments of freshwater basins

This paper presents the results of measurements of the Mo isotopic composition in the bottom sediments (BS) of freshwater basins. Mo isotopic ratios were measured using a multicollector inductively coupled plasma mass spectrometer (MC ICP MS). Efficient methods were used in this study for Mo separation from the elements of the sample matrix and correction for instrumental mass discrimination. This allowed us to achieve a high accuracy of 0.06, 0.08, and 0.14‰ (2 σ) for the measurement of ⁹⁷Mo/⁹⁵Mo, ⁹⁸Mo/⁹⁵Mo, and ¹⁰⁰Mo/⁹⁵Mo, respectively. The range of variations in Mo isotope ratios observed in the collected BS columns was ～2.2‰ in terms of δ⁹⁷Mo/⁹⁵Mo. The results obtained here suggest that geochemical processes occurring during Mo migration with land water can change the isotopic composition of Mo. It is pointed out that the potential use of Mo isotopic systematics for reconstructions of redox conditions in seawater over the geologic past requires the quantification of isotopic effects of Mo accompanying its migration on land and the extent of possible variations in the isotopic composition of Mo entering the ocean.     

地质样品中镥-铪同位素体系的化学分离与质谱测试新进展

对自1980年以来地质样品中Lu—Hf同位素体系的化学分离方法与质谱测试技术的最新进展进行了综述。着重介绍热电离质谱、热二次离子质谱和多接收电感耦合等离子体质谱（MC—ICP—MS）在测定Lu—Hf同位素时，针对不同类型的仪器、不同的样品所采用的各种化学分离方法和质谱测试技术。主要参考文献46篇。通过文献综述表明，MC—ICP—MS技术是当前进行Lu—Hf同位素测试的主要技术，Eichrom Ln—Spec树脂是一次进行Lu—Hf同位素体系化学分离的有效手段，和其他成熟的同位素体系（Rb—Sr、Sm—Nd、U—Pb）结合，成为今后具有很大发展空间的研究方向之一。     

High Precision Determination of 48Ca/42Ca Ratio by TIMS for Ca Isotope Fractionation Studies

For studies of mass-dependent fractionation of calcium isotopes in natural materials, the ⁴⁸Ca/⁴²Ca ratio is a superior choice to the conventionally measured ⁴⁴Ca/⁴⁰Ca ratio for two important reasons. These are (1) mass-dependent fractionation can be determined free from the effects of inherited or ingrown radiogenic ⁴⁰Ca and (2) this ratio increases the spread of measured isotopic masses by 50%, resulting in statistically better resolution of fractionation, assuming similar precision. A third, though strictly technical, advantage is the inherent ability of a mass spectrometer to measure ratios close to unity (⁴⁸Ca/⁴²Ca) more precisely than very small or large ratios (⁴⁴Ca/⁴⁰Ca). However, because of the very low natural abundance of both ⁴⁸Ca and ⁴²Ca, their ratio has been very difficult to measure, the only attempt so far being on a high mass resolution MC-ICP-MS with a precision of 0.33%. We report here determination of the ⁴⁸Ca/⁴²Ca ratio by the more commonly available and user-friendly multi-collector TIMS using a ⁴³Ca-⁴⁶Ca double-spike, with a significantly better precision of 0.18% (2s). The ⁴⁸Ca/⁴⁰Ca or ⁴⁴Ca/⁴⁰Ca ratio can also be measured in the same mass spectrometer run to provide complementary information on any radiogenic component.     

Assessment of Nanosecond Laser Ablation Multi‐Collector Inductively Coupled Plasma‐Mass Spectrometry for Pb and Sr Isotopic Determination in Archaeological Glass: Mass Bias Correction Strategies and Results for Corning Glass Reference Materials

This work presents an evaluation of various methods for in situ high‐precision Sr and Pb isotopic determination in archaeological glass (containing 100–500 μg g^?1 target element) by nanosecond laser ablation multi‐collector‐inductively coupled plasma‐mass spectrometry (ns‐LA‐MC‐ICP‐MS). A set of four soda‐lime silicate glasses, Corning A–D, mimicking the composition of archaeological glass and produced by the Corning Museum of Glass (Corning, New York, USA), were investigated as candidates for matrix‐matched reference materials for use in the analysis of archaeological glass. Common geological reference materials with known isotopic compositions (USGS basalt glasses BHVO‐2G, GSE‐1G and NKT‐1G, soda‐lime silicate glass NIST SRM 610 and several archaeological glass samples with known Sr isotopic composition) were used to evaluate the ns‐LA‐MC‐ICP‐MS analytical procedures. When available, ns‐LA‐MC‐ICP‐MS results for the Corning glasses are reported. These were found to be in good agreement with results obtained via pneumatic nebulisation (pn) MC‐ICP‐MS after digestion of the glass matrix and target element isolation. The presence of potential spectral interference from doubly charged rare earth element (REE) ions affecting Sr isotopic determination was investigated by admixing Er and Yb aerosols by means of pneumatic nebulisation into the gas flow from the laser ablation system. It was shown that doubly charged REE ions affect the Sr isotope ratios, but that this could be circumvented by operating the instrument at higher mass resolution. Multiple strategies to correct for instrumental mass discrimination in ns‐LA‐MC‐ICP‐MS and the effects of relevant interferences were evaluated. Application of common glass reference materials with basaltic matrices for correction of ns‐LA‐MC‐ICP‐MS isotope data of archaeological glasses results in inaccurate Pb isotope ratios, rendering application of matrix‐matched reference materials indispensable. Correction for instrumental mass discrimination using the exponential law, with the application of Tl as an internal isotopic standard element introduced by pneumatic nebulisation and Corning D as bracketing isotopic calibrator, provided the most accurate results for Pb isotope ratio measurements in archaeological glass. Mass bias correction relying on the power law, combined with intra‐element internal correction, assuming a constant ⁸⁸Sr/⁸⁶Sr ratio, yielded the most accurate results for ⁸⁷Sr/⁸⁶Sr determination in archaeological glasses     

High precision iron isotope measurements of terrestrial and lunar materials

We present the analytical methods that have been developed for the first high-precision Fe isotope analyses that clearly identify naturally-occurring, mass-dependent isotope fractionation. A double-spike approach is used, which allows rigorous correction of instrumental mass fractionation. Based on 21 analyses of an ultra pure Fe standard, the external precision (1-SD) for measuring the isotopic composition of Fe is ±0.14 ‰/mass; for demonstrated reproducibility on samples, this precision exceeds by at least an order of magnitude that of previous attempts to empirically control instrumentally-produced mass fractionation (Dixon et al., 1993). Using the double-spike method, 15 terrestrial igneous rocks that range in composition from peridotite to rhyolite, 5 high-Ti lunar basalts, 5 Fe-Mn nodules, and a banded iron formation have been analyzed for their iron isotopic composition. The terrestrial and lunar igneous rocks have the same isotopic compositions as the ultra pure Fe standard, providing a reference Fe isotope composition for the Earth and Moon. In contrast, Fe-Mn nodules and a sample of a banded iron formation have iron isotope compositions that vary over a relatively wide range, from δ⁵⁶Fe = +0.9 to −1.2 ‰; this range is 15 times the analytical errors of our technique. These natural isotopic fractionations are interpreted to reflect biological (“vital”) effects, and illustrate the great potential Fe isotope studies have for studying modern and ancient biological processes.     

高精度稳定锶同位素分析方法综述

近年来稳定Sr同位素在同位素地球化学领域越来越受到重视,在表生地球化学、古环境、考古学、地球内生作用及陨石等方面研究都取得了重要成果,这得益于高精度稳定Sr同位素分析方法的发展。文章总结了δ88/86Sr分析方法的关键技术要素。在化学提纯方面,文献中广泛使用Sr特效树脂,用离子交换法实现Sr元素的分离提纯,但Sr特效树脂价格昂贵,且具有难以消除的记忆效应,建议用阳离子树脂代替;在质谱分析方面,主要使用多接收电感耦合等离子体质谱（MCICP-MS）和热电离质谱（TIMS）进行测量,MC-ICP-MS测量具有比TIMS更高的测量效率,但是测量精度略低;对于质量歧视校正,目前使用较为广泛的方法有标样—样品间插法、Zr元素外部校正法以及双稀释剂法,其中双稀释剂法具有较高的测量精度,但在MC-ICP-MS上应用的相关研究较少。目前还缺乏对国际标准样品的δ88/86Sr的详细对比。因此,优化分析流程、提高测量精度以及更多标准样品δ88/86Sr的测定是需要加强的工作。     

Lead Isotopic Composition in Biogenic Certified Reference Materials Determined by Different ICP‐based Mass Spectrometric Techniques

This work presents data for the radiogenic Pb isotopic ratios (²⁰⁶Pb/²⁰⁷Pb and ²⁰⁸Pb/²⁰⁶Pb) in nine biogenic certified reference materials (NIST SRM 1515, 1566b, 1570a, 1573a, 1575a; BCR 100, BCR 101, BCR 670 and IAEA 359), which are suitable for analytical quality control in environmental research. The results were obtained using three different types of ICP‐based mass spectrometer (quadrupole‐based/magnetic sector field single‐collector ICP‐MS instruments and a multi‐collector ICP‐MS) and applying different mass bias correction procedures (calibrator‐sample bracketing and external Tl normalisation) with and without Pb separation from the matrix using ion exchange chromatography. In the majority of the samples, the measurements from all three of the ICP‐MS instruments were in agreement within ± 0.1%, despite the lower analytical precision of the single‐collector ICP‐MS instruments. We demonstrate that the presence of the sample matrix did not significantly influence the Pb isotopic ratios measured by magnetic sector field ICP‐MS, whereas the use of the two different mass bias corrections resulted in a systematic difference of 0.09% for the ²⁰⁸Pb/²⁰⁶Pb ratio.