Agilent ICP-MS Journal (May 2021, Issue 84)

Significance of the Topic

ICP-MS and ICP-QQQ techniques remain indispensable for trace element analysis across various fields, including food safety, materials characterization, and environmental monitoring. The Agilent ICP-MS Journal Issue 84 presents advances in sample preparation to minimize contamination in dried food, software integration for laser ablation workflows, and strategies to resolve spectral interferences using collision/reaction cell gases. These developments address critical needs for accuracy, throughput, and robust data management in high-sensitivity and high-throughput ICP-MS applications.

Objectives and Overview

Three primary studies are covered:

• Assessment of grinding and rinsing effects on trace element contamination in rice samples prior to acid digestion.
• Introduction of the HDIP LA-ICP-MS acquisition and data analysis platform as an alternative to traditional software plug-ins.
• Evaluation of helium cell gas with kinetic energy discrimination (KED) in ICP-QQQ to mitigate polyatomic interferences and control cell-formed reaction products.

Methodology and Instrumentation

Each study employed rigorous experimental protocols:

1. Dried food contamination study:
   
   • Sample sets: unprocessed, stainless steel–ground, and rinsed prior to digestion.
   • Analysis via Agilent 7900 ICP-MS measuring 24 elements.
2. Laser ablation workflow optimization:
   
   • HDIP software with Teledyne Cetac lasers and Agilent MassHunter for data acquisition.
   • Automated synchronization of laser shots with ICP-MS signals and advanced background correction.
3. Helium cell gas in ICP-QQQ:
   
   • Agilent 8900 ICP-QQQ using He collision mode and NH3/He reaction mode.
   • Investigation of interference removal for ArC+ on 52Cr+ and ClO+ on 51V+.

Main Results and Discussion

Key findings include:

• Grinding caused significant contamination in rice: Cr increased 20-fold; Al, Ti, V, Fe, Co, Ni, and Ba more than doubled. Rinsing reduced Al by 60% and Cr by 75%. Unprocessed samples provided representative trace profiles.
• HDIP enabled sub-millisecond alignment of ablation events with multichannel ICP-MS data, eliminated transfer errors, and accelerated method setup with automated optimization for high-throughput, high-resolution imaging.
• In He mode, optimized cell design achieved BEC <1 ppt and DL = 5 ppt for 52Cr in organic solvent. In NH3/He mode, helium buffer gas suppressed NH3+ clusters, yielding sub-ppt BEC and DL for 51V in 20 % HCl.

Practical Benefits and Applications

These advancements deliver:

• Enhanced food safety assessments by minimizing preparation-induced contamination.
• Streamlined laser ablation workflows and rapid data reduction, boosting lab productivity.
• Reliable, low-ppt quantification in challenging matrices for semiconductor chemicals and environmental samples.

Future Trends and Opportunities

Emerging directions include:

• Integration of advanced software platforms with real-time feedback for LA-ICP-MS imaging.
• Further development of collision/reaction cell chemistries to tackle new interferences.
• Machine learning–driven method development and predictive maintenance in high-throughput ICP-MS.

Conclusion

The combined improvements in sample handling, software integration, and cell gas strategies underscore the evolving capabilities of ICP-MS and ICP-QQQ. These innovations enable laboratories to achieve unparalleled sensitivity, accuracy, and efficiency in trace element analysis.

References

• US FDA, Elemental Analysis Manual (EAM) for Food and Related Products, April 2021.
• Van Malderen et al., Anal. Chem. 92 (8), 5756–5764 (2020).
• Van Elteren et al., Spectrochim. Acta Part B 140, 29–34 (2018).