Agilent ICP-MS Journal (February 2018. Issue 71)

Significance of the Topic

Precise determination of trace metal(loid) species and total elemental content is critical in environmental monitoring, petrochemical quality control, and consumer safety. Arsenic speciation in gas and liquefied gas streams affects polymer production and catalyst performance, while ultra-trace mercury detection in cosmetic products is mandatory to meet regulatory limits. Advanced ICP-MS techniques now enable simultaneous total and speciation analysis with rapid turnaround, high sensitivity, and robust interference removal.

Objectives and Overview of Studies

This issue presents three key developments and community updates:

• Simultaneous total arsenic and volatile arsenic compound analysis in gas and liquefied gas samples by GC-ICP-MS.
• Interference-free quantification of trace mercury in tungsten-rich cosmetic samples using Agilent 8900 ICP-QQQ in MS/MS mode.
• Highlights from the 7th Asia-Pacific Winter Conference on Plasma Spectrochemistry, including trends in nanoparticle and isotope-ratio analysis, plus on-demand webinars for laboratory productivity.

Methods and Instrumentation

• GC-ICP-MS System: Agilent 7890B GC with dual gas sampling valves, J&W GS-GasPro column, heated transfer line, coupled to Agilent 7900 ICP-MS via G3158D interface. Online dilution achieved with GasMix Aiolos II and Alytech vaporizer.
• ICP-QQQ System: Agilent 8900 triple-quadrupole ICP-MS with standard concentric nebulizer, double-pass spray chamber, 2.5 mm quartz injector, nickel cones. Operated in no-gas, He collision, O₂ single-quad, and O₂ MS/MS modes.

Main Results and Discussion

• Arsenic Speciation by GC-ICP-MS: A 5-minute method enables on-column separation of arsine (AsH₃) from column bypass flow. Detection limits of 2 ppt total As and 12 ppt AsH₃. Calibration was linear (r²>0.998) over 0.2–68 ppb. Synthetic and real propylene samples returned recoveries within 90–105%, confirming accuracy for gas and liquid phases.
• Mercury in Tungsten-Rich Cosmetics: Conventional ICP-MS suffered severe WO⁺/WOH⁺ interferences on 200Hg and 202Hg isotopes in a high-W matrix. Switching to O₂ MS/MS mode on the 8900 ICP-QQQ removed oxide interferences by converting WO⁺ to WO₂⁺, allowing interference-free on-mass detection of Hg⁺. All key isotopes (198–202Hg) measured consistently at ~0.02 µg/L. A 30 ppt Hg spike in a real sample gave 104% recovery.
• Conference Trends: APWC 2017 featured over 210 attendees. Major themes included single-cell and single-nanoparticle ICP-MS analysis, laser ablation, isotope dilution, and speciation. Agilent presentations demonstrated the benefits of MS/MS in controlling reaction chemistry and advanced nanoparticle quantification protocols.

Benefits and Practical Applications

• Enables simultaneous total and species-specific elemental analysis in a single run, reducing sample handling and analysis time.
• Delivers ppt-level detection for regulatory compliance in petrochemical feedstocks and cosmetic safety testing.
• Offers predictable, reproducible interference removal using MS/MS, streamlining QA/QC workflows in environmental, food, and pharmaceutical laboratories.

Future Trends and Potential Applications

Continued growth in single-particle and single-cell ICP-MS will drive demand for high-speed, high-resolution MS/MS techniques. Automation of speciation workflows, integration of online dilution and vaporization systems, and expansion into clinical pharmacokinetics and food safety testing are expected. Advances in reaction cell chemistries and data-processing algorithms will further enhance sensitivity and selectivity.

Conclusion

The combination of GC-ICP-MS and ICP-QQQ in MS/MS mode represents a new standard for trace and speciation analysis. These methods deliver unmatched sensitivity, speed, and interference control, meeting the stringent requirements of industrial, environmental, and regulatory testing.

Použitá instrumentace

• Agilent 7890B GC with J&W GS-GasPro column and heated GC-ICP-MS interface (G3158D).
• GasMix Aiolos II dilutor and Alytech vaporizer chamber.
• Agilent 7900 ICP-MS
• Agilent 8900 Triple-Quadrupole ICP-MS with He and O₂ cell gas capabilities.

Reference

1. Freije-Carrelo L., Moldovan M., García Alonso J.I., VO T.D.T., Ruiz Encinar J., “Instrumental Setup for Simultaneous Total and Speciation Analysis of Volatile Arsenic Compounds in Gas and Liquefied Gas Samples,” Anal. Chem. 2017, 89, 5719–5724.
2. Agilent Technologies, “Simultaneous Total and Speciation Analysis of Volatile Arsenic Compounds in Gas and Liquefied Gas Samples Using GC-ICP-MS,” Application Note 5991-8799EN, 2017.
3. U.S. Food and Drug Administration, Federal Food, Drug, and Cosmetic Act (FD&C Act), Cosmetic Regulations, 2017.
4. Sugiyama N., Woods G., “Interference-Free Mercury Analysis in Cosmetics Using ICP-MS/MS,” Agilent Application Note 5991-0892EN, 2012.
5. Song J., Zeng X., Yan D., Wu W., “Trace Mercury Determination in Complex Matrices by ICP-QQQ,” Agilent Application Note 5991-5400EN, 2015.
6. Balcaen L., Bolea-Fernandez E., Resano M., Vanhaecke F., “Advanced Reaction-Cell Strategies for ICP-MS/MS,” Anal. Chim. Acta 2015, 894, 7–19.