Reliable and productive analysis of food samples using single quadrupole ICP-MS

Importance of the Topic

Reliable quantification of toxic and nutritional trace elements in food matrices is critical for consumer safety, regulatory compliance and quality assurance. Modern food testing laboratories must screen a vast variety of samples to confirm levels of contaminants such as arsenic, cadmium, mercury and lead are below established maximum limits, while also verifying the presence of essential nutrients. Single quadrupole ICP-MS, enhanced by argon gas dilution and kinetic energy discrimination, offers a powerful solution for handling complex sample matrices and achieving both high sensitivity and wide dynamic range in routine food analysis.

Objectives and Study Overview

This application note outlines a large-scale evaluation of the Thermo Scientific iCAP MSX single quadrupole ICP-MS system, equipped with argon gas dilution (AGD) and helium KED, for the analysis of over 7,000 food samples within an eight-week period. The primary goals were to demonstrate robust, day-to-day stability of the instrument, maintain data accuracy across diverse matrices, and minimize downtime by leveraging automated dilution and maintenance-monitoring features.

Methodology

Samples (0.5 g dry or 2 g wet) were prepared via closed-vessel microwave acid digestion in 50 mL final volume. Digests were placed directly on an autosampler; in-line AGD provided automatic dilution, eliminating manual steps. Helium collision gas in KED mode was employed to suppress polyatomic interferences, while a mathematical correction addressed doubly charged species from rare earth elements. A typical run time of under two minutes per sample was achieved using the Step Ahead autosampler feature. Quality control included analysis of multiple certified reference materials to assess accuracy and precision.

Instrumentation

The analytical setup comprised:

• Thermo Scientific iCAP MSX ICP-MS with argon gas dilution module (AGD Level 5)
• Thermo Scientific iSC-65 autosampler with Step Ahead capability
• iCAP MX Series concentric nebulizer and cyclonic quartz spray chamber (2.7 °C)
• Quartz torch (2.5 mm ID injector), Ni-tipped interface cones
• Collision/reaction cell operating in He-KED mode (4.4 mL/min He, 3 V KED)
• RF power 1,550 W, auxiliary gas 0.8 L/min, coolant gas 14 L/min
• Qtegra Intelligent Scientific Data Solution software with Get Ready automation and HAWK consumables assistant for maintenance scheduling

Results and Discussion

Accuracy was validated with various CRMs covering nutrient elements (Na, Mg, Al, P, K, Ca, Mn, Fe, Cu, Zn, Se) and toxic analytes (As, Se, Mo, Cd, Sn, Pb). Major element recoveries ranged from 90–105% (85–120% for P and Fe), while toxic elements in rice flour SRM returned 91–101% (Pb at 83%). Over 25 analytical days spanning eight weeks (total >7,000 samples), the system maintained stable internal standard recoveries (80–120%, often 90–115%) and showed negligible drift. No interface cleaning or maintenance interventions were required, highlighting the effectiveness of AGD in reducing matrix load on the plasma and interface components.

Practical Benefits and Applications

• Automated sample dilution reduces manual handling, minimizes signal suppression and drift, and improves throughput.
• He-KED mode combined with mathematical correction ensures accurate quantification of low-level contaminants in complex matrices.
• Continuous operation for extended sequences (>12 h/day) without maintenance interruptions maximizes laboratory productivity.
• Integrated software automation supports unattended startup, performance verification and predictive maintenance alerts.

Future Trends and Opportunities

Advances in automation and data integration will further streamline high-throughput food analysis. Future developments may include tighter integration with LIMS and AI-driven data processing for rapid anomaly detection. Expanding isotopic fingerprinting workflows on single quadrupole platforms could support authentication of geographic origin and enhanced traceability. Continued innovation in interface design and gas dilution technology will push sensitivity and robustness boundaries for next-generation food safety testing.

Conclusion

The Thermo Scientific iCAP MSX ICP-MS with argon gas dilution and helium KED delivers a robust, reliable solution for large-scale food analysis. Over 7,000 samples processed in eight weeks demonstrated excellent accuracy, prolonged uptime and minimal maintenance, ensuring consistent compliance with regulatory requirements and facilitating high laboratory productivity.

References

• COMMISSION REGULATION (EU) 2023/915 of 25 April 2023 on maximum levels for certain contaminants in food and repealing Regulation (EC) No 1881/2006.
• GB-2762-2017 National Food Safety Standard for Maximum Levels of Contaminants in Foods, China.
• Accurate and reliable multielement analysis of alternative protein foods using ICP-MS. Thermo Scientific Application Note 002282.
• AOAC Official Method 2015.01 Heavy Metals in Food Inductively Coupled Plasma–Mass Spectrometry First Action 2015.
• Complete and comprehensive interference removal in ICP-MS: Can this be achieved? Thermo Scientific Smart Note 000214.