Analysis of silicon, phosphorus and sulfur in 20% methanol using the Agilent 8800 Triple Quadrupole ICP-MS

Significance of the Topic

Trace analysis of silicon, phosphorus and sulfur in organic solvents is critical across semiconductor manufacturing, hydrocarbon processing and life sciences research. Ultralow levels of these elements can compromise wafer quality, catalyst performance or protein function and require reliable, sensitive detection.

Aims and Study Overview

This study evaluates the Agilent 8800 Triple Quadrupole ICP-MS for simultaneous quantification of Si, P and S in 20% methanol. Methanol was spiked with standards (1–50 ppb) and analyzed to compare two single-quad collision modes with three MS/MS reaction modes using H2, He and O2 gases under identical plasma and ion optic settings.

Methodology

Standards were prepared by diluting ultrapure methanol 1:5 with water and spiking at four levels (1, 5, 10, 50 ppb). Five operational modes were tested:

• Single quadrupole with helium collision gas.
• Single quadrupole with hydrogen collision gas.
• MS/MS with hydrogen reaction gas.
• MS/MS with helium reaction gas.
• MS/MS with oxygen reaction gas.

Used Instrumentation

The Agilent 8800 combines two quadrupoles (Q1 and Q2) surrounding an octopole reaction system (ORS3). Q1 isolates the target m/z entering the cell, ORS3 controls reaction chemistry, and Q2 selects either on-mass or mass-shift product ions for detection.

Main Results and Discussion

MS/MS modes delivered substantial improvements in background equivalent concentrations (BECs) and detection limits (DLs) compared to single-quad operation:

• Silicon: Single-quad H2 mode BEC 25.5 ppb, DL 0.12 ppb; H2 MS/MS BEC 2.2 ppb, DL 0.03 ppb.
• Phosphorus: Single-quad He mode BEC 3.8 ppb, DL 0.63 ppb; O2 MS/MS BEC 0.4 ppb, DL 0.05 ppb.
• Sulfur: Not measurable in single-quad modes due to intense matrix interferences; O2 MS/MS BEC ~3 ppb, DL ~0.1 ppb.

O2 MS/MS was optimal for sulfur, while H2 MS/MS yielded the best results for phosphorus and silicon. The MS/MS architecture maintains isotopic patterns and prevents off-mass overlaps, ensuring predictable and efficient interference removal.

Benefits and Practical Applications

The Agilent 8800 offers high sensitivity and robust interference suppression for critical process fluids. It eliminates the need for expensive xenon, supports compound-independent calibration in life science assays, and enables simultaneous multielement analysis in industrial QA/QC.

Future Trends and Opportunities

Future developments may include coupling MS/MS with HPLC for speciation studies, exploring alternative reaction gases, expanding metallomic profiling, and integrating automated in-line monitoring for real-time process control.

Conclusion

The Agilent 8800 ICP-Triple Quad significantly enhances trace-level determination of silicon, phosphorus and sulfur in methanol matrices by combining precise mass filtering with controlled reaction chemistry. It delivers ppb-to-sub-ppb detection limits and reliable interference removal, meeting the stringent demands of semiconductor, chemical and life science applications.