Agilent ICP-MS Journal (May 2011 – Issue 46)

Significance of Advanced ICP-MS in Environmental and Speciation Analysis

The growing complexity of industrial and environmental samples demands robust analytical methods capable of handling high matrix loads and providing reliable trace-level quantification. Modern ICP-MS techniques, coupled with novel sample introduction systems and hyphenated separation approaches, play a crucial role in regulatory monitoring, process control and public health protection.

Objectives and Study Overview

This issue presents four key developments: high-throughput analysis of flue gas desulfurization (FGD) wastewaters by ICP-MS, application of compound-independent calibration for arsenic speciation by HPLC-ICP-MS, evolution of a PFA micro-concentric nebulizer for enhanced aerosol generation, and insights from an expert user meeting on GC-ICP-MS method sharing.

Methodology and Instrumentation

• Agilent 7700x ICP-MS with High Matrix Introduction (HMI) and helium collision mode for polyatomic interference removal and robust long-sequence analysis.
• ISIS-DS discrete sampling system for high sample throughput in 89-sample sequences.
• Agilent 1260 HPLC fitted with arsenic speciation column and guard columns for separation of As species at pH 11 mobile phase.
• Compound-independent calibration (CIC) using As(V) standard to quantify multiple arsenic species without species-specific standards.
• Development of Savillex C-Flow PFA micro-concentric nebulizers (50 μL/min and 200 μL/min) featuring a supported capillary tip for uniform droplet size and reduced blockages.
• GC-ICP-MS coupling interface hardware and software enhancements discussed by European and North American expert users.

Main Results and Discussion

• FGD Wastewater Analysis: A validated SOP met USEPA criteria, achieving 40 ppb recoveries in synthetic high-matrix samples with calibration and QC checks within ±15 % across 89 analyses. Method detection limits remained low without excessive dilution.
• Arsenic Speciation: Twelve undiluted urine samples analyzed over a 13 h run showed CIC/CSC ratios of 0.89–1.16 for arsenobetaine, MMA, As(III), DMA and As(V), demonstrating CIC’s viability to simplify calibration workflows.
• PFA Nebulizer Evolution: The C-Flow design produced a narrower droplet size distribution (~9 µm) and improved transport efficiency. Its larger capillary ID reduced clogging, supporting analyses of high-silicon and phosphoric acid matrices.
• GC-ICP-MS Expert Meeting: Over 30 speakers shared best practices in applications ranging from petrochemical distillation to isotope dilution, fostering collaborative development of new interface designs and software tools.

Benefits and Practical Applications

• Rapid, high-throughput ICP-MS workflows for heavily contaminated matrices with minimal sample preparation.
• Simplified calibration using CIC reduces reliance on costly or unavailable species-specific standards.
• Enhanced sample introduction systems ensure stable long-term performance and reduced maintenance.
• Cross-disciplinary exchange of GC-ICP-MS methods accelerates innovation in trace organic and inorganic speciation.

Future Trends and Potential Applications

• Expansion of CIC to other elements and unexpected species in complex matrices.
• Further miniaturization and inert materials in nebulizer and interface design for ultralow volume clinical and geochemical analyses.
• Integration of real-time data analytics and predictive diagnostics for continuous monitoring in industrial processes.
• Development of standardized interlaboratory protocols combining GC-ICP-MS and HPLC-ICP-MS for comprehensive speciation studies.

Conclusion

The combination of advanced ICP-MS platforms, innovative sample introduction technologies and hyphenated separation techniques enables reliable trace analysis in challenging matrices. These developments support regulatory compliance, research innovation and industrial quality control, laying the groundwork for further enhancements in sensitivity, throughput and calibration simplicity.

Reference

• Sakai T, Wilbur S. Routine Analysis of Toxic Arsenic Species in Urine Using HPLC with ICP-MS. Agilent Technologies Application Note 5989-5505EN, 2010.
• Todoli JL, Mermet JM. Spectrochimica Acta Part B 61 (2006):239–283.
• Agilent Technologies. Analysis of Flue Gas Desulfurization Wastewaters by ICP-MS. Application Note 5990-8114EN, 2011.