Trace Element Analysis in Geological Samples

The analysis of trace elements in geological samples underpins our understanding of crustal evolution, mineral exploration and environmental monitoring. Trace elements, present at concentrations ranging from parts per million to parts per billion, require highly sensitive analytical techniques to quantify their concentrations and isotopic compositions. Modern workflows typically involve careful sample preparation—comprising selection, pulverisation and chemical digestion—to liberate elements from complex mineral matrices. Following digestion, elements are measured by techniques such as Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and its multi-collector variants, which offer sub-ppb detection limits and high precision. Advances in closed-vessel microwave digestion, alkali fusion and novel reagent formulations have improved dissolution efficiency for refractory phases. Coupled with laser ablation for in situ analysis, these approaches provide both bulk and spatially resolved elemental data. Such methods have driven progress in geochronology, provenance studies and ore deposit characterisation. Their global significance is underscored by applications ranging from deep-sea hydrothermal vent research to assessments of pollution and resource sustainability. Integrating complementary techniques and robust quality control standards has fostered a more complete and accurate elemental and isotopic record of Earth processes.

Research from Nature Portfolio

Recent studies have refined acid digestion protocols for low-grade gold analysis in mine tailings, demonstrating that reverse aqua regia, with or without hydrofluoric acid, achieves complete mineral breakdown and linear calibration between 5 and 100 µg L−1. By integrating size fractionation and depot analysis, free-milling gold fractions exceeding 75 % were quantified with recoveries of 80–82 %, yielding uncertainties comparable to traditional fire assay methods. This streamlined approach reduces operational time and environmental impact, illustrating the potential of tailored digestion chemistries to enhance trace metal recovery from complex matrices.

Trace Element Analysis in Geological Samples publication trend

The graph below shows the total number of articles in trace element analysis in geological samples across all publications each year (not limited to Nature Index journals).

Technical terms

Acid digestion: A sample preparation method using mineral acids such as HNO₃, HF or combinations to dissolve geological materials for elemental analysis.

Inductively Coupled Plasma Mass Spectrometry (ICP-MS): Analytical technique that ionises dissolved samples in an argon plasma and separates ions by mass–to–charge ratio for trace-element quantification.

Multi-collector ICP-MS (MC-ICP-MS): A variant of ICP-MS equipped with multiple detectors to measure isotopic ratios with high precision and accuracy.

Reverse aqua regia: An acid mixture with reversed proportions of hydrochloric and nitric acids, often combined with HF, to enhance digestion of refractory phases.

Alkali fusion: A decomposition technique using solid fluxes such as lithium borate or sodium peroxide at high temperature to achieve complete dissolution of silicate minerals.

Laser ablation: A sample introduction method where a laser beam vapourises a solid surface, allowing direct, spatially resolved elemental or isotopic analysis when coupled to ICP-MS.

References

1. Study of Ultrasound-Assisted Low-Pressure Closed Acid Digestion Method for Trace Element Determination in Rock Samples by Inductively Coupled Plasma Mass Spectrometry. Molecules (2025).
2. Chemical analysis of low grade gold from mine tailings after size fractionation and acid digestion using reverse aqua regia. Scientific Reports (2025).
3. Sample preparation for geochemical analysis: Strategies and significance. Advances in Sample Preparation (2022).
4. A Microwave Digestion Technique for the Analysis of Rare Earth Elements, Thorium and Uranium in Geochemical Certified Reference Materials and Soils by Inductively Coupled Plasma Mass Spectrometry. Molecules (2020).
5. Recent advances in MC-ICP-MS applications in Earth and environmental sciences: Challenges and solutions. Geosystems and Geoenvironment (2022).
6. Rare Earth Elements Determination by Inductively Coupled Plasma Mass Spectrometry after Alkaline Fusion Preparation. Analytica—A Journal of Analytical Chemistry and Chemical Analysis (2022).
7. Data Quality in Geochemical Elemental and Isotopic Analysis. Minerals (2022).