Enhancing the productivity of food sample analysis with ICP-MS

Importance of the Topic

Accurate determination of elemental composition in food is essential for safety assessment and regulatory compliance. The ability to measure both trace and major elements in diverse food matrices with a single analytical setup enhances laboratory efficiency and data reliability.

Objectives and Study Overview

This work evaluates a single-configuration Agilent ICP-MS method combining helium collision mode and discrete sampling to quantify a wide range of elements in four certified food reference materials. Key aims include interference suppression, sensitivity across nine orders of magnitude, and throughput improvement.

Methodology

• Sample Preparation: Four CRMs (NIST SRM 1548a, SRM 2976, NRC DORM3, SRM 8415) were microwave-digested (HNO₃/H₂O₂) and diluted to 50 mL, yielding up to 5 g/L matrix.
• Calibration: Multi-element standards prepared in 6% HNO₃/0.5% HCl, covering 0.5–50 µg/L for trace elements and up to 5 mg/L for majors. No matrix matching required.

Used Instrumentation

• ICP-MS: Agilent 7700x with 3rd-generation ORS3 cell.
• Sample Introduction: MicroMist concentric nebulizer, quartz Peltier-cooled spray chamber (2 °C), quartz torch with 2.5 mm injector.
• Collision Gas: Helium in KED mode; dynamic switching between no gas and He.
• Discrete Sampling: Agilent ISIS-DS system to minimize uptake and rinse times.

Main Results and Discussion

• Calibration Performance: Linear responses (R>0.9997), detection limits in ng/L range, dynamic range up to mg/L.
• Interference Suppression: He mode effectively removed polyatomic interferences across multiple isotopes, with isotope agreement within ±7%.
• Accuracy: Measured concentrations in all four CRMs agreed with certified values for major, interfered, and non-interfered elements.
• Throughput: ISIS-DS reduced sample cycle from 5 min to 1.2 min without compromising sensitivity or accuracy.

Benefits and Practical Applications

• Single-run multi-element analysis across a wide concentration range.
• High sample throughput and reduced maintenance.
• Robust interference removal without reactive gases.

Future Trends and Possibilities

• Further automation and high-throughput workflows in food QA/QC.
• Extension to complex matrices and regulatory testing.
• Integration of advanced cell gases or hybrid collision-reaction approaches.

Conclusion

The combined use of helium collision mode and ISIS-DS on the Agilent 7700x ICP-MS allows streamlined, accurate, and rapid multi-element analysis of food samples, meeting the demands of modern food safety laboratories.

Reference

• Application Note, Agilent Technologies, 2017, Publication number: 5991-0107EN.