The Jet Interface: improving sensitivity of trace element analysis

Importance of the Topic

The ability to detect trace elements with high sensitivity is critical in fields such as environmental monitoring, geosciences and biomedical research. Enhancements to the interface of HR-ICP-MS instruments can significantly expand detection limits and improve data quality.

Objectives and Study Overview

This work compares the standard interface of a Thermo Scientific™ Element™ XR HR-ICP-MS to the newly developed Jet Interface. Experiments were conducted under wet and dry plasma conditions using tune solutions, a glass reference material and an organic tissue sample. Additional tests employed laser ablation (LA-ICP-MS) to assess the interface upgrade in bioimaging applications.

Methodology and Instrumentation

The Jet Interface comprises a high-capacity, air-cooled dry interface pump (100 m3/h), a Jet sample cone and an X skimmer cone, all engineered to optimize ion transmission.
Experimental setups:

• Wet plasma: Twinnabar™ cyclonic spray chamber, 200 µL/min MicroMist™ nebulizer.
• Dry plasma: Aridus3™ desolvating nebulizer, 100 µL/min PFA nebulizer.
• LA-ICP-MS: NWR 193™ laser; He carrier gas (600 mL/min), N2 assistant gas (5 mL/min).

All plasma conditions were tuned to minimize oxide formation (ThO/Th = 0.2) and maintain U/Th ≈ 1.1.

Main Results and Discussion

Solution analysis:

• Wet plasma: Jet Interface delivered a 4–5× sensitivity increase for light isotopes, 2–3× for mid-mass isotopes and >1× for heavy isotopes compared to the standard interface.
• Dry plasma: Sensitivity improved by an average factor of ~7× under desolvated conditions.

Laser ablation:

• Glass standard (NIST 610): Overall sensitivity gain of ~4× with Jet Interface; light isotopes saw up to 10× enhancement.
• Organic bio-sample: Breast cancer tissue labeled with Cd-antibodies showed similar sensitivity improvements, enabling high-resolution semi-quantitative elemental mapping.

These results confirm that the optimized cone geometry and enhanced vacuum capacity of the Jet Interface substantially increase ion transmission into the mass analyzer.

Benefits and Practical Applications

Improved sensitivity enables:

• Ultra-trace analysis of environmental and geochemical samples.
• Enhanced detection in bioimaging and medical diagnostics.
• Faster analysis times and lower detection limits in QA/QC laboratories.

Future Trends and Applications

Potential developments include integration with multicollector ICP-MS for isotopic ratio precision, coupling with next-generation laser sources for subcellular imaging and further optimization of interface pumping to approach theoretical detection limits. Advances in data processing and machine learning may also exploit the higher signal-to-noise ratios achieved.

Conclusion

Upgrading to the Jet Interface on the Element XR HR-ICP-MS yields consistent, multi-fold sensitivity enhancements across wet, dry and laser ablation modes. These gains broaden the scope of trace element and isotopic studies in diverse scientific disciplines.

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