Nu Instruments | Interference-Free Selenium Isotope Measurements Using Sapphire CRC
Selenium isotope analysis can be complicated by argon-based and isobaric interferences. This application note demonstrates how the Sapphire Collision/Reaction Cell enables simultaneous, interference-free measurement of all major selenium isotopes using optimised reaction gas chemistry.
Selenium isotopes are important tools in environmental, biological and geochemical research. Accurate measurements are often challenging because of multiple spectral interferences and hydride formation.
The Sapphire Collision/Reaction Cell was evaluated using both He-H₂ and He-N₂ gas mixtures. Results showed that a He-N₂ configuration effectively removes argon-based interferences while minimising hydride formation.
The approach delivers fully mass-dependent isotope fractionation behaviour, excellent repeatability and strong resistance to concentration mismatching. These capabilities enable reliable selenium isotope measurements across a wide range of applications.
Key Takeaways:
- He-N₂ collision cell conditions provide efficient interference-free selenium analysis.
- Short-term repeatability better than 35 ppm was demonstrated for ⁸⁰Se/⁷⁸Se.
- Robust measurements are maintained with concentration differences of up to 20%.
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