Agilent ICP-MS Journal (March 2006 – Issue 26)

Significance of the Topic

The comparability and reliability of analytical measurements are critical for regulatory compliance, international trade and enforcement of environmental, health and safety standards. ICP-MS, combined with isotope‐dilution strategies and traceability frameworks, offers a robust route to harmonized and high‐precision determinations across laboratories worldwide.

Objectives and Study Overview

Issue 26 of the Agilent ICP-MS Journal (March 2006) presents:

• An overview of chemical metrology via ICP-MS at National Metrology Institutes (NMIs) and key reference analyses in CCQM comparisons.
• A user profile of LCABIE, highlighting advanced speciation research across environmental, food and clinical chemistry.
• Service and support updates for preventive maintenance, consumable selection and new instructional resources.
• Community news on new ICP-MS users, trade events and recent publications.

Methodology and Instrumentation

Chemical Metrology and Traceability

• Implementation of international comparability through the CIPM Mutual Recognition Arrangement and CCQM key comparisons.
• Use of isotope dilution mass spectrometry (IDMS) with “approximate matching” to minimize bias and uncertainty.

Species-specific and Collision-Cell IDMS

• HPLC-ICP-MS with 117Sn‐enriched TBT spike and accelerated solvent extraction for tributyltin in sediment (CCQM-K28).
• ICP-MS with H₂/He collision cell for 78Se/77Se IDMS in salmon after microwave digestion (CCQM-K43).

Speciation and Hyphenated Techniques at LCABIE

• Reversed-phase, ion-exchange and graphitic carbon HPLC couplings to quadrupole ICP-MS.
• Capillary and nano-HPLC interfaces (sheathless and low-flow nebulizers) for selenopeptide mapping and amino-acid analysis.
• Laser ablation-ICP-MS mapping of selenium‐containing proteins in gel electrophoresis.
• GC-ICP-MS with isotopically labeled standards and reverse isotope dilution for organomercury and organotin quantification.

Key Results and Discussion

• CCQM-K28: LGC’s reference value for TBT in sediment (1.046 ± 0.093 nmol g⁻¹) agreed closely with the international consensus.
• CCQM-K43: Se in salmon determined by IDMS (7.04 ± 0.034 mmol kg⁻¹) showed excellent agreement among participating NMIs.
• LCABIE demonstrated detection limits down to fg‐level for Se species using nano-HPLC-ICP-MS and sub‐ppb quantification of selenoamino acids in serum via two-dimensional SEC-RP HPLC-ICP-MS.
• GC-ICP-MS with RID achieved pg L⁻¹ detection of volatile organomercury and organotin species in water and biological matrices.

Benefits and Practical Applications

• Establishment of traceable, matrix‐certified reference materials and calibration services to underpin proficiency testing and quality assurance in analytical laboratories.
• Species-specific IDMS ensures accurate quantification of trace and toxic element forms in environmental monitoring, food safety and clinical diagnostics.
• Advanced ICP-MS hyphenations enable studies of metal‐biomolecule interactions, pollutant fate and single‐cell metal distributions.
• Preventive maintenance programs and genuine consumables safeguard instrument performance, reduce downtime and lower lifetime operating costs.

Used Instrumentation

• Agilent 7500 Series ICP-MS (7500a/i/s/c/ce/cs) with octopole collision/reaction cell technology.
• Agilent 1100 Series HPLC, capillary and nano-HPLC modules, C18 and graphitic carbon columns.
• Accelerated Solvent Extractor (ASE), microwave digestion systems.
• Laser ablation accessories and optimized low‐flow nebulizers.
• Agilent ICP-MS chromatographic and data analysis software.

Future Trends and Potential Applications

• Expansion of chemical metrology key comparisons to additional elements and complex matrices.
• Further miniaturization of separation techniques—including single‐cell and subcellular analyses—coupled to ICP-MS.
• Development of multidimensional and high-resolution chromatography with collision/reaction cell enhancements to tackle increasingly challenging interferences.
• Broader adoption of traceable reference methods by routine and regulatory laboratories worldwide.
• Ongoing improvements in automation, maintenance diagnostics and remote support to maximize uptime.

Conclusion

Advances in ICP-MS instrumentation, isotope dilution methodologies and international metrology frameworks have made traceable, high-accuracy chemical measurements a reality. Collaborative efforts through CCQM and national institutes, coupled with strategic maintenance and support, are essential to sustain reliable analytical performance and address emerging needs in environmental, food, clinical and industrial applications.

References

1. Sargent M., “Traceability,” in Encyclopedia of Analytical Science, P. Worsfold et al., Eds., Academic Press, 2005, pp. 477–485.
2. Sargent M., “The UK Chemical Calibration Facility at LGC,” VAM Bulletin, No. 27, 2002, pp. 18–22.
3. Sargent M., “Metrology in chemistry: a different approach to comparable analytical results,” J. Anal. At. Spectrom., vol. 20, 2005, pp. 1017–1018.
4. Sargent M., “UK delivery of traceable chemical measurements in the 21st century,” Accreditation and Quality Assurance, vol. 8(10), 2003, pp. 480–482.
5. Sargent M., Harte R., Harrington C., Guidelines for Achieving High Accuracy in IDMS, RSC, Cambridge, 2002.
6. Wahlen R., Wolff-Briche C., “Comparison of GC-ICP-MS and HPLC-ICP-MS for species‐specific IDMS of TBT in sediment,” Anal. Bioanal. Chem., vol. 377, 2003, pp. 140–148.
7. Bueno M., et al., “Sheathless capillary HPLC-ICP-MS for selenopeptide mapping,” Anal. Chem., vol. 75, 2003, pp. 6837–6842.
8. Bueno M., et al., “Nano-HPLC-ICP-MS interface for fg-level Se detection,” Anal. Chem., vol. 78, 2006, pp. 965–971.
9. Bueno M., et al., “Isotope-dilution SEC-RP HPLC-ICP-MS quantification of selenoamino acids in serum,” Anal. Chem., vol. 76, 2004, pp. 6635–6642.