WCPS: Determination of Heavy Metals and Nutrient Elements in Alternative Protein Foods Using ICP-MS

Significance of the topic

Ensuring the safety and nutritional quality of alternative protein foods is critical as these products gain market share. Inductively coupled plasma mass spectrometry (ICP-MS) offers rapid, sensitive multi-element analysis, enabling compliance with Good Manufacturing Practices and regulatory limits for heavy metals and essential nutrients.

Objectives and study overview

This work applies the US FDA Elemental Analysis Manual method EAM 4.7 to determine 12 elements in digested samples of insect, fungal, and plant-based proteins. The goals are to validate digestion and instrumental procedures, assess accuracy using certified reference materials, and demonstrate the method’s suitability for routine food safety testing.

Methodology

Samples underwent closed-vessel microwave digestion following EAM 4.7:

• Approximately 0.5 g of sample was combined with 5 mL HNO3 and 1 mL H2O2 in MARS 6 vessels.
• The program ramped to 200 °C over 20 min, held for 15 min, then cooled.
• Digests received 0.5 mL HCl and were diluted to 50 g with deionized water.
• Certified reference materials (NIST 1566b Oyster Tissue, NRC DOLT-4 Dogfish Liver, DORM-4 Fish Protein) verified digestion and calibration accuracy.

Used Instrumentation

This study employed an Agilent 7850 ICP-MS configured with:

• Octopole Reaction System (ORS4) collision cell and Shield Torch for helium mode operation with kinetic energy discrimination.
• Ultra High Matrix Introduction (UHMI) for direct analysis of up to 25 % total dissolved solids, minimizing matrix suppression.
• ISIS discrete sampling accessory for high-speed uptake and rapid valve switching to boost throughput.
• MicroMist concentric nebulizer, quartz torch with 2.5 mm injector, nickel-plated sampling and skimmer cones.
• Operating parameters included 1600 W RF power, 0.80 L/min carrier gas, 5 mL/min helium, and KED at 5 V.

Results and discussion

Analysis of reference materials yielded recoveries of 91–113 %, meeting the FDA EAM 4.7 criteria of 80–120 %. Doubly-charged interferences on As, Se, and Zn were effectively reduced via half-mass correction in the MassHunter software. Spike recovery tests for cricket protein, reishi mushroom, almond meal, and chick-pea flour showed recoveries within 98–116 %, confirming method accuracy. IntelliQuant semiquantitative scans revealed additional elements such as sulfur, strontium, iodine, and trace rare earth elements, supporting non-target screening.

Practical benefits and applications

The validated method delivers reliable multi-element data with minimal matrix effects, reduced calibration complexity, and enhanced sample throughput. It supports quality assurance and regulatory compliance in food safety laboratories, especially for novel alternative protein matrices.

Future trends and potential applications

Advancements may include expanded collision cell chemistries for further interference removal, integration of real-time process monitoring, high-throughput robotics for large sample batches, and enhanced non-target screening to detect emerging contaminants in alternative protein ingredients.

Conclusion

The Agilent 7850 ICP-MS, when operated according to FDA EAM 4.7, provides accurate, precise, and efficient analysis of heavy metals and nutrient elements in alternative proteins, meeting stringent QC criteria and enabling robust food safety assessments.

References

1. Gray PJ, Mindak WR, Cheng J US FDA Elemental Analysis Manual 4.7 Inductively Coupled Plasma-Mass Spectrometric Determination of Arsenic, Cadmium, Chromium, Lead, Mercury, and Other Elements in Food Using Microwave Assisted Digestion Version 1.2 February 2020