Agilent ICP-MS Journal (August 2002 – Issue 13)

Importance of the topic

Interference control in inductively coupled plasma mass spectrometry is crucial for accurate trace element and speciation analysis across complex matrices such as environmental, biological and industrial samples. The Agilent octopole reaction system enables efficient removal of common polyatomic species while preserving sensitivity for target analytes. High matrix tolerance, direct analysis of challenging solvents and integrated hyphenation improve throughput and expand application scope in routine and research laboratories.

Objectives and study overview

This issue compiles developments in collision/reaction cell technology, case studies of ICP-MS deployment in environmental and reference laboratories, advanced arsenic speciation by HPLC-ICP-MS, direct hydrocarbon analysis, and software enhancements to facilitate multi-mode data acquisition. Customer profiles illustrate real-world performance of the Agilent 7500c system under high-matrix and regulatory environments.

Methodology and instrumentation used

Instrument platforms and techniques featured include

• Agilent 7500c ICP-MS with octopole reaction system operating in hydrogen and helium modes
• ShieldTorch ion source for narrow, low-energy ion distributions
• H₂ and He cell gases for reaction and collision regimes
• Dionex 300 HPLC and Agilent 1100 Series coupled to ICP-MS for arsenic speciation
• PFA-20 low-flow concentric nebulizer, cooled spray chamber and oxygen flow module for direct hydrocarbon analysis
• Agilent ChemStation software Rev. B.01.03 with enhanced multi-tune functionality

Main results and discussion

Hydrogen-mode reactions efficiently attenuate plasma-based species such as ArO⁺, CO⁺ and N₂⁺ with minimal analyte loss, as shown by exponential decay of ArO signal versus H₂ flow. Helium collision mode combined with kinetic energy discrimination rejects residual low-energy polyatomic ions while transmitting monatomic analytes. Case studies report robust performance on seawater and salt-rich matrices, achieving quantification of over 30 elements at ng/L levels and throughput above 100 samples per day without sample‐specific tuning. The HPLC-ICP-MS method achieved baseline separation of 17 arsenic species within 16.5 min, enabling comprehensive speciation in marine biota with low-ng/L detection limits. Direct pentane analysis demonstrated sub-ppb determination of Hg, Se and As without digestion. Enhanced multi-tune allows simultaneous acquisition in normal, reaction and collision modes for flexible method development and post-acquisition mode selection.

Benefits and practical applications

The octopole reaction system and ShieldTorch combination simplifies trace multielement analysis in unknown, high-matrix samples by avoiding element-specific tuning and preserving sensitivity. Integrated sample introduction and advanced software streamline workflows from environmental monitoring and food safety to forensic and industrial QA/QC. Direct solvent analysis reduces sample preparation time and contamination risks, while HPLC coupling permits detailed speciation relevant to toxicity and metabolic studies.

Future trends and applications

Advancements are anticipated in novel reaction gas chemistries to address emerging interferences, tighter integration of separation techniques (GC, CE, microfluidics), and further automation with intelligent method selection. Expansion into isotope-dilution ICP-MS will improve metrological traceability. Enhanced connectivity with laboratory information management systems and real-time data analytics will boost throughput, data quality and decision support.

Conclusion

Agilent’s octopole reaction system, operating in hydrogen and helium modes and complemented by the ShieldTorch and enhanced software, provides universal interference suppression with maintained sensitivity and high throughput. Real-world applications from seawater to hydrocarbons confirm its robustness and versatility. Coupling with HPLC extends capabilities to full multicomponent speciation, establishing the 7500c platform as a comprehensive solution for modern analytical challenges.

References

• Yamada N., Takahashi J., Sakata K. The effects of cell-gas impurities and kinetic energy discrimination in an octopole collision cell ICP-MS under non-thermalized conditions. JAAS (in publication).
• Leonhard P., Pepelnik R., Prange A., Yamada N., Yamada T. Analysis of diluted sea-water at the ng/L level using an ICP-MS with an octopole reaction cell. J. Anal. At. Spectrom., 2002, 17, 189.