Agilent ICP-MS Journal (April 2018. Issue 72)

Significance of the Topic

Semiconductor device fabrication and cutting-edge research demand ultra-trace analysis of metallic contaminants to ensure product yield, performance, and reliability. Inductively coupled plasma mass spectrometry (ICP-MS), and in particular triple quadrupole ICP-MS (ICP-QQQ), has become the analytical cornerstone for monitoring impurities in high-purity materials, process chemicals, and complex sample matrices across industries including microelectronics, environmental monitoring, and life sciences.

Objectives and Study Overview

This issue of the Agilent ICP-MS Journal explores:

• How semiconductor industry requirements have driven instrument and methodological innovations in Agilent ICP-MS systems.
• Applications of ICP-MS and ICP-QQQ for analysis of ultrapure acids and ultrapure water used in wafer processing.
• Case studies on trace metal determination in novel matrices, such as e-cigarette aerosols.
• Highlights from the Winter Plasma Conference demonstrating emerging trends in plasma spectrochemistry.

Methodology and Instrumentation

Agilent ICP-MS platforms incorporate a series of key design features to meet stringent detection requirements:

• Off-axis ion lenses and cool plasma technology (HP 4500) to reduce matrix effects on alkali and alkaline earth elements.
• Benchtop footprint and inert sample introduction for clean-room compatibility and low-contamination handling of sub-milliliter volumes.
• Stainless-steel chassis and optimized flow paths (7700 series) for minimal background.
• Multiple reaction cell modes and MS/MS capability (8800 and 8900 ICP-QQQ) to control spectral interferences and achieve sub-ppt detection limits for up to 50 elements in aggressive matrices.
• Adaptations for specialized techniques such as vapor-phase decomposition, surface metal extraction, gas chromatography coupling, and laser ablation.

Main Results and Discussion

Analysis of High-Purity Nitric Acid: Direct measurement of 49 elements in 68% HNO3 using the 8900 ICP-QQQ yielded sub-ppt detection limits and linear response down to parts-per-trillion levels, simplifying sample preparation and avoiding dilution artifacts.

Analysis of High-Purity Hydrochloric Acid: In 20% and 36% HCl samples, 50 elements including all SEMI Tier-C targets were quantified with single-digit ppt or sub-ppt detection limits. Background equivalent concentrations remained well below the 100 ppt maximum industry specifications.

Trace Metals in E-Cigarette Aerosols: Single-quadrupole ICP-QQQ analysis of e-cigarette refill liquids, tank reservoirs, and generated aerosols revealed that heating coils leach Fe, Pb, Ni, Cr, Mn, and other metals into the vapor phase at concentrations often exceeding health-based benchmarks.

Conference Insights: The Winter Plasma Conference highlighted growing adoption of triple quadrupole ICP-MS for nanoparticle and single-cell analysis, advanced speciation using HPLC and GC interfaces, and the importance of software tools for method development and interference management.

Benefits and Practical Applications

ICP-QQQ enables:

• Comprehensive contamination control in semiconductor manufacturing, supporting feature sizes down to 10 nm through ultrapure chemicals analysis.
• Rapid quality assurance of precursors and process chemicals in microelectronics, photovoltaics, and advanced materials.
• Trace-level environmental monitoring of emerging contaminants.
• Speciation and isotopic ratio measurements in geochemistry, biomedical research, and food safety.

Future Trends and Opportunities

Ongoing miniaturization of semiconductor devices and tightening of purity standards will drive further enhancements in ICP-MS sensitivity, interference reduction, and automation. Emerging applications include single-cell metabolomics, real-time online monitoring, high-resolution isotope ratio analysis, and integration with machine learning for predictive maintenance and method optimization.

Advances in sample introduction—such as aerosol desolvation, microfluidic interfaces, and plasma source innovations—will broaden the scope of ICP-MS to challenging matrices, while multi-modality platforms combining LC, GC, and laser ablation will expand speciation capabilities.

Conclusion

Agilent’s sustained innovation in ICP-MS instrumentation—from cool plasma to MS/MS triple quadrupole systems—has addressed the evolving needs of the semiconductor industry and beyond. The combination of sub-ppt detection limits, robust interference control, and flexible sample handling positions ICP-QQQ as a versatile tool for trace analysis across research, quality control, and regulatory sectors.

Used Instrumentation

• Agilent 4500 ICP-MS (cool plasma, off-axis lenses)
• Agilent 7700 ICP-MS (stainless-steel clean chassis)
• Agilent 8800 ICP-QQQ (MS/MS, multi-mode cell)
• Agilent 8900 ICP-QQQ (enhanced sensitivity, low-background flow paths)
• Supporting modules: automated sample pumps, autosamplers, vapor-phase decomposition units, GC and HPLC interfaces, laser ablation systems

References

• SEMI C35-0708, Specifications and Guidelines for Nitric Acid (2008).
• SEMI C27-0708, Specifications and Guidelines for Hydrochloric Acid (2008).
• Analysis of Trace Metal Impurities in High Purity Hydrochloric Acid Using ICP-QQQ, Agilent Technologies Application Note 5991-8675EN.
• Direct Analysis of Trace Metal Impurities in High Purity Nitric Acid Using ICP-QQQ, Agilent Technologies Application Note 5991-8798EN.