High Sensitivity, Fast Scanning, Sector Field ICP-MS – Improving Sensitivity for Laser Ablation with the Jet Interface

Significance of the Topic

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) demands high sensitivity for applications requiring small spot sizes, trace element detection at low concentrations, and precise isotope ratio measurements, such as geochronology and bioimaging. Sector field ICP-MS equipped with a Jet Interface offers the potential to substantially enhance sensitivity, enabling ultratrace analysis and improved spatial resolution.

Objectives and Study Overview

This study evaluates the sensitivity gains achieved by coupling the Thermo Scientific Element XR sector field ICP-MS with a high-capacity Jet Interface to a fast-scanning laser ablation system. Performance is compared against a quadrupole-based iCAP TQ and a multicollector Neptune XT for U-Pb isotopic analysis of NIST SRM 610 and two reference zircons (91500 and GJ-1).

Methodology and Instrumentation

A Teledyne Photon Machines Analyte G2 193 nm excimer laser with HelEx ablation cell was used to ablate reference materials under consistent conditions (35 µm spot, 3 J/cm², 7 Hz, 30 s). Three ICP-MS platforms were tested: Element XR with Jet Interface, iCAP TQ with high-sensitivity cones, and Neptune XT with Jet Interface. Sample ion yields were assessed via an ESI Apex Omega desolvating nebulizer using 1 ppb solutions of Li, Fe, Sr, Nd, Hf, Pb, and U. Dwell times were 26 ms for most isotopes and 48 ms for 207Pb.

Main Results and Discussion

Sector field analysis with Jet Interface delivered sample ion yields exceeding 1% for four of seven elements, increasing with isotope mass. LA-ICP-MS sensitivity on Element XR was over 20× higher than the iCAP TQ and 3.5× higher than Neptune XT for 238U signals. Equivalent counting rates indicated an 8 µm spot on Element XR matched a 35 µm spot on a quadrupole system, and a 2.5 µm spot provided similar sensitivity. Enhanced sensitivity reduced uncertainty in 207Pb/206Pb age determinations by approximately half under identical ablation conditions.

Benefits and Practical Applications

The Jet Interface enables ultratrace detection limits with minimal sample consumption, supporting high-resolution elemental imaging and geochronological studies. Its extended dynamic range, achieved through automated switching of detector modes, and fast electrostatic scanning across 202Hg–238U simplify multielement and isotope ratio measurements without mass tuning adjustments.

Future Trends and Potential Applications

Continued development of high-sensitivity sector field ICP-MS with Jet Interface is expected to drive smaller laser spot analyses (<5 µm), enhanced spatial resolution in bioimaging, and deeper insights into trace element distributions. Integration with advanced data processing platforms and coupling with femtosecond lasers may further improve precision and expand applications in environmental monitoring, nuclear forensics, and materials science.

Conclusion

Coupling a sector field ICP-MS (Element XR) with a Jet Interface significantly boosts LA-ICP-MS sensitivity, lowers detection limits, and enhances isotope ratio precision. These improvements facilitate ultratrace and high-resolution analyses that are challenging for conventional quadrupole instruments.

References

• J. Zheng et al. Evaluation of a new sector-field ICP-MS with Jet Interface for ultratrace determination of Pu isotopes: from femtogram to attogram levels. J. Nucl. Radiochem. Sci. 15 (2017) 7.
• W. Men et al. Establishing rapid analysis of Pu isotopes in seawater to study the impact of the Fukushima nuclear accident in the Northwest Pacific. Scientific Reports 8 (2018) 1892.
• N. Jakubowski et al. Inductively coupled plasma- and glow discharge plasma-sector field mass spectrometry Part II: Applications. J. Anal. At. Spectrom. 26 (2011) 727.

Used Instrumentation

• Laser: Teledyne Photon Machines Analyte G2 193 nm excimer with HelEx ablation cell
• ICP-MS Systems: Thermo Scientific Element XR with Jet Interface; Thermo Scientific iCAP TQ with high-sensitivity cones; Thermo Scientific Neptune XT with Jet Interface
• Desolvating Nebulizer: ESI Apex Omega