A straightforward tandem column separation procedure is presented for the separation of Sr, Nd, Pb, and Hf from silicate materials. It allows rapid purification, without any intervening evaporation, of these four elements of great interest in Earth science and cosmochemistry. After sample loading, the upper Sr Spec column adsorbs Sr and Pb, while the lower TODGA Spec column adsorbs Hf and Nd. Strontium-lead and hafnium–neodymium elements are then back-extracted from the Sr Spec and TODGA Spec columns, respectively. The whole separation procedure, including column setup, cleaning, and pre-conditioning, takes approximately eight hours for separating a batch of 25 samples. The proposed procedure offers significant improvement in separation efficiency of these often-used four elements, compared with conventional four column methods. Fractions of Sr, Nd and Pb are then measured by TIMS and the Hf fraction is determined by MC-ICP-MS. The stability of this procedure was demonstrated by replicate measurements of ⁸⁷Sr/⁸⁶Sr, ¹⁴³Nd/¹⁴⁴Nd, ¹⁷⁶Hf/¹⁷⁷Hf, ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb isotope ratios of eight international silicate rock reference materials, spanning a wide range of bulk compositions. The analytical results obtained in this study agree well with published data. The external reproducibility (2RSD, n = 8) of standard BCR-2 was ±0.0026% for ⁸⁷Sr/⁸⁶Sr, ±0.0020% for ¹⁴³Nd/¹⁴⁴Nd, ±0.0049% for ¹⁷⁶Hf/¹⁷⁷Hf, and ±0.026–0.034% for ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb isotope ratios.

Thermal ionization mass spectrometry (TIMS) is considered the most accurate technique for determining Sr–Nd–Pb isotopic ratios in geological samples. However, time-consuming and complex sample separation procedures greatly hinder the instrumental measurement efficiency. In this study, a single-column separation chemistry procedure for Sr–Nd–Pb from single rock dissolution was developed. The chemistry procedure was designed to minimize the number of evaporation steps and considerably shorten the separation time, enabling high throughput for TIMS. In contrast to conventional three-column separation procedures (∼3 days), this technique was characterized by high efficiency superiority in terms of separation time (∼8 hours), a 3-fold enhancement in the separation efficiency. The stability of our procedure was demonstrated by replicated TIMS measurements of ⁸⁷Sr/⁸⁶Sr, ¹⁴³Nd/¹⁴⁴Nd, ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb ratios for six international silicate rock reference materials, spanning a wide range of bulk compositions. The analytical results obtained for these standards agreed well with published data. The external reproducibility (2 RSD, n = 10) of a BCR-2 standard sample was ±0.0020% for ⁸⁷Sr/⁸⁶Sr, ±0.0023% for ¹⁴³Nd/¹⁴⁴Nd, and ±0.021–0.033% for ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb ratios.

Sm–Nd isotopic system is a powerful tracer and dating tool in geochemistry and cosmochemistry. Thermal ionization mass spectrometry (TIMS) is the benchmark method for obtaining high precision Nd isotope ratios. Traditionally, a two-step separation was employed in order to obtain high purity Nd fraction, which makes the sample preparation time-consuming. In this study, we present a new method to directly obtain precise and accurate Nd isotope ratios of geological samples without Sm–Nd separation. The key point is to well correct isobaric interferences of ¹⁴⁴Sm on ¹⁴⁴Nd for this method. The accurate intensity of ¹⁴⁴Sm can be obtained using ¹⁴⁷Sm/¹⁴⁴Sm ratio of 4.87090 and mass discrimination factor of Sm (β_Sm), which is achieved using ¹⁴⁷Sm/¹⁴⁹Sm ratio of 1.08583 with Russell equation. Consequently, the real intensity of ¹⁴⁴Nd was achieved, then also raw ¹⁴⁶Nd/¹⁴⁴Nd, ¹⁴³Nd/¹⁴⁴Nd ratios. Finally, ¹⁴³Nd/¹⁴⁴Nd ratio is normalized using ¹⁴⁶Nd/¹⁴⁴Nd ratio of 0.7219 following exponential law. The accuracy of this method is validated by replicating TIMS measurements for thirteen international reference materials of silicate rock, spanning a wide range of Sm/Nd from 0.13 to 0.46 and bulk compositions. The measured ¹⁴³Nd/¹⁴⁴Nd ratios of the rock standards are in good agreement with the reported values of within error of ±0.004%. Our new method shortens the analytical procedure and significantly improves sample throughput which greatly contributes to those studies requiring a large dataset and quick analysis.

The oxygen (O) and neodymium (Nd) isotopic composition of monazite provides an ideal tracer of metamorphism and hydrothermal activity. Calibration of the matrix effect and monitoring of the external precision of monazite O–Nd isotopes with microbeam techniques, such as secondary ion mass spectrometry (SIMS) and laser ablation-multicollector-inductively coupled plasma-mass spectrometry (LA-MC-ICPMS), require well-characterized natural monazite standards for precise microbeam measurements. However, the limited number of standards available is impeding the application of monazite O–Nd isotopes. Here, we report on the RW-1 monazite as a potential new working reference material for microbeam analysis of O–Nd isotopes. Microbeam measurements by electron probe microanalysis (EPMA), SIMS, and LA-MC-ICPMS at 10–24 µm scales have confirmed that it is homogeneous in both elemental and O–Nd isotopic compositions. SIMS measurements yield δ¹⁸O values consistent, within errors, with those obtained by laser fluorination techniques. Precise analyses of Nd isotope by thermal ionization mass spectrometry (TIMS) are consistent with mean results of LA-MC-ICPMS analyses. We recommend δ¹⁸O = 6.30‰ ± 0.16‰ (2SD) and ¹⁴³Nd/¹⁴⁴Nd = 0.512282 ± 0.000011 (2SD) as being the reference values for the RW-1 monazite.

Thermal ionization mass spectrometry and multiple-collector inductively coupled plasma mass spectrometry are considered to be “gold standards” for the determination of the isotope ratios of Sr–Nd and Hf in geological samples because of the extremely high precision and accuracy of these methods. However, the sample throughputs are hindered by time-consuming and tedious chemical procedures. Three-step ion exchange resin separation is traditionally employed to purify Sr–Nd–Hf from matrix elements. In this study, a one-step Sr–Nd–Hf separation scheme was developed to process geological samples. The separation scheme is based on the combined use of conventional AG50W-X12 cation-exchange resin and LN Spec extraction chromatographic material without any intervening evaporation step. The protocol not only prevents cross-contamination during operation using multiple-stage ion exchange resins but also significantly improves the efficiency of sample preparation. The stability of our chemical procedure was demonstrated by replicate measurements of ⁸⁷Sr/⁸⁶Sr, ¹⁴³Nd/¹⁴⁴Nd, and ¹⁷⁶Hf/¹⁷⁷Hf ratios in six international reference materials of silicate rocks. The analytical results obtained for these standard rocks compare well with the published data. The external reproducibility (2 SD, n = 10) of a BCR-2 standard sample was ±0.000018 for ⁸⁷Sr/⁸⁶Sr, ±0.000010 for ¹⁴³Nd/¹⁴⁴Nd, and ±0.000014 for ¹⁷⁶Hf/¹⁷⁷Hf.