New Analysis Protocol for Stable Isotopes by a Standard Doping Method─An Example of Antimony

Area of Science:

• Geochemistry
• Analytical Chemistry
• Isotope Geochemistry

Background:

• Traditional stable antimony isotope analysis is complex and unsuitable for samples with low antimony concentrations (<1 μg/g).
• Existing methods face challenges in matrix separation and achieving high precision for trace antimony levels.

Purpose of the Study:

• To develop a streamlined and accurate protocol for stable antimony isotope analysis.
• To enable precise antimony isotopic measurements in geological samples with low antimony content.

Main Methods:

• A novel protocol employing a single AG50W-X8 resin column for antimony separation.
• Antimony standard doping to facilitate accurate isotopic composition determination.
• Inductively coupled plasma mass spectrometry (ICP-MS) for isotopic measurements, with corrections for instrumental mass bias.

Main Results:

• The method effectively separates antimony from complex matrices, allowing accurate analysis even at low concentrations.
• Reproducibility for δ¹²³Sb was excellent (<0.03‰ 2SD), validated across multiple standard solutions and geological samples.
• The antimony consumption per sample is significantly reduced to as low as 5 ng.

Conclusions:

• The proposed standard doping method offers a robust and efficient approach for stable antimony isotope analysis.
• This technique overcomes limitations of previous methods, particularly for trace antimony in geological materials.
• The methodology provides a valuable new tool for geochemical and environmental studies involving antimony isotopes.