Agilent ICP-MS Journal (October 2013 – Issue 55)

Importance of the Topic

The accurate quantification of trace and major elements in complex matrices is critical across geochemistry, environmental monitoring, food and pharmaceutical safety, and consumer product regulation. Modern ICP-MS and LC-ICP-MS techniques address the need for high sensitivity, fast throughput, and robust interference removal to meet stringent regulatory limits and productivity goals.

Objectives and Overview

This collection of studies and applications aims to demonstrate:

• The integration of discrete sampling (ISIS-DS), automated aerosol dilution (HMI) and helium collision mode for high-matrix rock and mineral digests.
• Establishment of a metals testing center through the Agilent–RSSL partnership, enhancing analytical capabilities for food, drink and pharmaceuticals.
• Matrix-matched calibration in a synthetic blood diluent to improve accuracy and precision of trace metal determinations.
• Development of an LC-ICP-MS method for Cr(III)/Cr(VI) speciation in toy materials under the EN71-3:2012 migration limits.

Methodology and Instrumentation

Instrumentation and key methods used include:

• Agilent 7700x ICP-MS with nickel cones, MicroMist nebulizer, ISIS-DS sample introduction, HMI for plasma optimization, and helium collision gas to remove polyatomic interferences.
• Agilent 8800 ICP-QQQ for advanced interference control in semiconductor, nuclear and environmental applications.
• Agilent 1260 Bio-inert LC coupled to the 7700x for anion exchange separation of Cr species.
• Matrix matching of calibration standards using a synthetic blood diluent (n-butanol, NH4OH, H4EDTA, Triton X-100 with added NaCl and CaCl2).

Main Results and Discussion

• High-throughput analysis of six certified rock reference materials achieved 365 analyses in under 9 hours (avg. 87 s/sample) with calibration linearity r>0.9999 and method detection limits of 0.7–40 µg/kg for most elements.
• Matrix-matched calibration in synthetic blood eliminated ISTD bias, yielding near-perfect correlation with proficiency test reference values using 103Rh, 185Re or 205Tl as ISTDs.
• The LC-ICP-MS method fully resolved Cr(III) and Cr(VI) peaks at 0.95 and 1.67 min, with solution DLs of 3.1 ppt (Cr(III)) and 2.0 ppt (Cr(VI)), sample MDLs of 1.6 and 1.0 µg/kg, and spike recoveries of 96–111%.
• The Agilent–RSSL collaboration equipped a new laboratory with ICP-MS, ICP-OES, AAS and MP-AES platforms, expanding capacity for elemental impurity testing under evolving pharmacopoeial and food safety regulations.

Benefits and Practical Applications

These combined technologies and protocols offer:

• Single-instrument workflows for multi-element analysis at trace to major levels, reducing reliance on separate ICP-OES runs.
• Enhanced robustness to high total dissolved solids and strong acids in mineral digests.
• Accurate quantitation in biological matrices through matrix-matched calibration, simplifying ISTD selection.
• Regulatory compliance for toy safety (EN71-3), pharmaceutical elemental impurities (USP <232>, <233>, Ph.Eur. 2.4.20, 5.20) and food contaminant limits (EC 1881/2006).

Future Trends and Opportunities

Emerging directions include:

• Broader adoption of ICP-QQQ for routine interference removal in environmental and clinical labs.
• Further automation of sample introduction and matrix-dilution systems for higher throughput and reproducibility.
• Integration of single-particle and speciation analyses with advanced data analytics and AI-driven method optimization.
• Expanded partnerships between instrument vendors and contract laboratories to accelerate method development and disseminate best practices.

Conclusion

Agilent’s ICP-MS platforms, combined with discrete sampling, automated aerosol dilution, helium collision/reaction cell technology and tailored chromatographic separation, deliver the sensitivity, speed and confidence required for multi-element and speciation analyses in complex matrices. These solutions support regulatory compliance, laboratory productivity and ongoing innovation across industrial, environmental, food, pharmaceutical and consumer safety applications.

Reference

1. Agilent Technologies, Investigations into the use of helium collision mode and aerosol dilution for ultra-trace analysis of metals in mineral reference materials, White Paper 5991-2811EN
2. Agilent application note 5991-2991EN: Determination of essential and toxic metals in blood by ICP-MS with calibration in synthetic matrix
3. Agilent application note 5991-2878EN: LC-ICP-MS method for Cr(III) and Cr(VI) in toy materials to meet EN71-3:2012
4. EN71-3:2012 European Toy Safety Standard