Analysis of Inorganic Arsenic, Cadmium, Lead, and Mercury in Baby Foods by ICP-MS

Significance of the Topic

Infants and young children are highly vulnerable to toxic elements such as inorganic arsenic, cadmium, lead, and mercury due to their lower body weight and limited dietary variety. Contamination of baby foods with these metals poses a serious risk to neurological and physical development. In response, the U.S. Baby Food Safety Act 2021 proposes stringent action levels for these elements to ensure safer nutrition during critical growth stages.

Objectives and Study Overview

This application note demonstrates a reliable analytical workflow for the routine determination of inorganic arsenic (iAs), cadmium (Cd), lead (Pb), and mercury (Hg) in a wide range of baby foods. The study verifies compliance with proposed regulatory limits by applying FDA Elemental Analysis Manual (EAM) methods for multi-element analysis and arsenic speciation.

Methodology

Samples were prepared by microwave-assisted acid digestion following FDA EAM section 4.7. Calibration standards and internal standards were used to quantify 12 elements. Quality control included certified reference materials, fortified method blanks, and fortified analytical portions. Arsenic speciation employed HPLC-ICP-MS using isocratic anion exchange to separate As(III) and As(V).

Used Instrumentation

• Agilent 7850 ICP-MS with ORS4 collision cell and Ultra High Matrix Introduction (UHMI)
• Agilent SPS 4 autosampler and standard glass nebulizer/spray chamber
• Agilent 1260 HPLC system for arsenic speciation
• CEM MARS 6 iWave closed-vessel microwave digestion system
• ICP-MS MassHunter software with IntelliQuant for rapid elemental screening

Main Results and Discussion

Detection limits achieved by the 7850 ICP-MS were one to two orders of magnitude below FDA EAM nominal limits. Recoveries for certified reference materials and fortified samples fell within 80–120%, demonstrating accuracy across diverse matrices. In survey samples, cadmium exceeded the proposed 5 ppb action level in two non-cereal products, while inorganic arsenic was detectable in several foods. Lead and mercury remained below detection limits. Arsenic speciation of rice cereals revealed iAs concentrations above both FDA guidance (100 ppb) and the proposed 15 ppb limit.

Benefits and Practical Applications

• Single-run ICP-MS analysis of major and trace elements with minimal reruns due to wide linear dynamic range
• Effective interference removal via helium collision cell and half-mass correction
• Rapid matrix assessment using IntelliQuant to optimize dilution and UHMI settings
• Seamless integration of HPLC and ICP-MS for targeted inorganic arsenic speciation
• Compliance with evolving regulatory requirements for baby food safety

Future Trends and Opportunities

Advances may include faster screening methods, expanded use of ICP-MS/MS for enhanced interference control, automated sample preparation, and real-time monitoring of contaminants. Development of portable or in-line sensors could further improve safety assurance in production and supply chains.

Conclusion

The Agilent 7850 ICP-MS coupled with HPLC-ICP-MS offers a robust, sensitive, and user-friendly solution for monitoring inorganic arsenic, cadmium, lead, and mercury in baby foods. This workflow meets FDA EAM quality criteria and supports manufacturers and testing laboratories in achieving compliance with the Baby Food Safety Act 2021.

Reference

1. US House of Representatives Committee on Oversight and Reform. Baby Foods Are Tainted with Dangerous Levels of Arsenic, Lead, Cadmium, and Mercury. February 4, 2021.
2. US House of Representatives. The Baby Food Safety Act of 2021.
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6. US FDA. Closer to Zero: Action Plan for Baby Foods. April 2021.
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