WCPS: AGILENT 8800 TRIPLE QUADRUPOLE ICP-MS WINTER PLASMA CONFERENCE 2012 POSTERS

Significance of the Topic

The removal of polyatomic and isobaric interferences is critical to realizing the full potential of ICP-MS in trace and ultra-trace analysis. Conventional single-quadrupole instruments often struggle with spectral overlaps (e.g., CoO on As, SeHx on Se, UH on Pu, Xe on I) and limited abundance sensitivity, restricting accurate quantification in environmental, semiconductor, biological, and nuclear applications.

Objectives and Study Overview

Across a series of Winter Plasma Conference presentations, Agilent Technologies showcased the new 8800 triple-quadrupole ICP-MS (ICP-QQQ) and demonstrated its ability to:

• Eliminate oxide and polyatomic interferences for elements such as As, Ti, P, V, Cr, Zn, and Se using novel reaction-cell gas modes (O₂, H₂, NH₃).
• Improve ion optics and vacuum design to maintain high sensitivity and abundance sensitivity.
• Enable isotope-ratio and isotope-dilution analysis for challenging radionuclides (¹²⁹I, Pu isotopes) and selenium with absolute accuracy.

Methodology and Instrumentation

• Instrument: Agilent 8800 Triple Quadrupole ICP-MS with ORS³ octopole reaction cell and dual quadrupoles (Q1 pre-cell mass filter, Q2 post-cell analyzer).
• Ion optics: Five-stage differential pumping, upstream Q1 with unit mass resolution, downstream Q2 matching Agilent 7700 design.
• Cell gases: O₂ (mass-shift reactions), H₂ or He (collision mode), NH₃(+He) for charge-transfer.
• MS/MS mode: Q1 set to target mass (1 amu window) rejects non-target ions, providing uniform cell conditions.
• Single-Quad mode: Q1 as RF-only guide for improved sensitivity on non-interfered masses.

Main Results and Discussion

• As in 100 ppm Co and 10 ppm Zr matrices (1% HNO₃): O₂ MS/MS mode reduced ⁷⁵AsO⁺ interference from CoO₂⁺ and Zr⁺ to 29 ppt residual, versus 63 ppt in single-quad, achieving lowest BEC and BEC-equivalent concentration (BEC-EQC).
• Ti in high Si or Cu/Zn matrices: O₂ mass-shift (TiO⁺) with Q1 at m/z 48 removed Zn and Ni overlaps; He/H₂O₂ collisional modes suppressed sulfur interferences in H₂SO₄. Calibration LODs down to tens of ppt in acid matrices.
• P in 20% HNO₃ and HCl: NH₃(+H₂) reaction generated P(NH₃)ₓ product ions, fully eliminating HNO₃-P and Cl- based interferences; BECs of 0.07–0.2 ppb and limits of detection below 0.5 ppb.
• ¹²⁹I/¹²⁷I ratios: O₂ charge-transfer removed ¹²⁹Xe⁺ background to instrument blank, enabling measurement of 10⁻⁶–10⁻⁸ ratios in NIST SRM 3231 with BEC 0.04 ng/L and DL 0.07 ng/L.
• Pu surrogates (Bi⁺) in 20 mg/L U: NH₃ MS/MS mode reduced UH⁺ by >5 orders, maintained Bi⁺ signal, demonstrating potential for Pu analysis in nuclear matrices.
• Se isotope-dilution (OIDA): O₂(+H₂) mass-shift allowed free measurement of ⁷⁸Se, ⁸⁰Se, ⁸²Se. Online spiking of ⁸²Se enriched standard achieved 95–105% recovery in multiple CRMs (except certain milk matrices), with 100 ppt–5 ppb range accuracy without mass-bias correction.

Benefits and Practical Applications

• Universal interference removal across a broad element range with predictable gas-phase chemistry.
• High sensitivity and ultra-low BEC/LOD, enabling accurate quantification in complex, high-matrix samples.
• Compatibility with online isotope dilution for absolute accuracy in critical trace analyses.
• Flexible operation modes (MS/MS, Single-Quad, collision) tailored to specific analytical challenges.

Future Trends and Opportunities

• Extension to other challenging analytes (e.g., lanthanoids, actinides, halogens) with optimized gas chemistries.
• Integration with rapid sample-introduction systems for high-throughput workflows in environmental and semiconductor QA/QC.
• Development of automated isotope-dilution protocols for routine CRM and biolabel applications.
• Enhanced data-processing algorithms for real-time interference correction and isotope-ratio monitoring.

Conclusion

The Agilent 8800 ICP-QQQ, with its MS/MS capability and advanced reaction-cell chemistry, effectively overcomes longstanding spectral-interference and abundance-sensitivity limitations of conventional ICP-MS. These innovations enable accurate, sensitive analysis from semiconductor chemicals to radionuclide and isotope-dilution applications, expanding the scope of ICP-MS in research and industry.

Instrumentation Used

• Agilent 8800 Triple Quadrupole ICP-MS with ORS³ reaction cell
• MicroFlow PFA-100 and MicroMist nebulizers
• Quartz and PFA spray chambers, PFA and platinum injectors
• Cell gases: O₂, H₂, He, NH₃ (+He)

References

John W. Olesik and Deanna R. Jones. Journal of Analytical Atomic Spectrometry, 2006, 21, 141–159.
Giuseppe Centineo, Jose Angel Rodriguez Castrillon and Esther Munoz Agudo. Agilent Technologies Application Note, 5990-9171EN.
A. Henrion. Fresenius Journal of Analytical Chemistry, 1994, 350, 657–658.