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

Importance of the Topic

The presence of inorganic arsenic, cadmium, lead and mercury in baby foods poses significant risks to infants and toddlers due to their higher food intake per body weight and developing organ systems. In response to evidence of elevated contaminant levels, the US Baby Food Safety Act 2021 proposes stringent action limits for these toxic elements to protect early childhood health.

Objectives and Study Overview

This application note evaluates the performance of an Agilent 7850 ICP-MS, coupled with HPLC-ICP-MS for arsenic speciation, in the quantification of inorganic arsenic (iAs), Cd, Pb and Hg across a range of commercial baby foods. The study addresses compliance with proposed US regulatory limits and demonstrates a single-batch microwave digestion workflow and inline quality control.

Methodology

The analysis followed the FDA Elemental Analysis Manual (EAM) 4.7 for total element determination and EAM 4.11 for arsenic speciation. Puréed baby food samples and NIST food reference materials were digested using closed-vessel microwave digestion (8 mL HNO₃ + 1 mL H₂O₂). Calibration standards spanned ppb levels in 3 % HNO₃/0.5 % HCl, with internal standards (Sc, Ge, Rh, In, Tb, Lu, Bi) added online. Quality control included method blanks, fortified blanks, fortified analytical portions (FAPs) and continuing calibration verifications (CCVs) inserted every ten samples.

Instrumentation Used

• Agilent 7850 ICP-MS with Octopole Reaction System (ORS4) and Ultra High Matrix Introduction (UHMI)
• Agilent 1260 HPLC for iAs speciation
• CEM MARS 6 iWave closed-vessel microwave digestion system
• Agilent SPS 4 autosampler

Main Results and Discussion

Detection limits achieved by ICP-MS were one to two orders of magnitude below EAM nominal limits. SRM recoveries (n=2) ranged 89–106 % for certified elements. Spike recoveries in beef medley and fruit/vegetable blends were 87–117 % (±1σ), meeting ±20 % criteria. Instrument stability over 48 h showed internal standard recoveries within ±20 %. Total matrix solids were rapidly assessed via IntelliQuant to select appropriate UHMI settings. Quantitative analysis of 11 baby foods revealed Cd exceeded the proposed 5 ppb action level in two non-cereal products; Pb and Hg remained below detection. Inorganic arsenic speciation by HPLC-ICP-MS in rice-based cereals (n=31) yielded iAs levels exceeding both the proposed 15 ppb and FDA’s 100 ppb limits in all samples.

Benefits and Practical Applications

• Single-batch digestion and universal He cell mode simplify multi-element workflows.
• UHMI enables direct analysis of high-solids samples with minimal matrix effects.
• IntelliQuant offers rapid semiquantitative screening for up to 78 elements, guiding dilution and interference correction.
• Coupled HPLC-ICP-MS provides robust inorganic arsenic speciation, critical for regulatory compliance.

Future Trends and Potential Applications

As regulatory pressure intensifies, demand for routine multi-element and speciation analysis in baby foods will grow. Anticipated advancements include faster chromatographic separations, triple-quadrupole ICP-MS for enhanced interference removal, integration of automated sample prep, and cloud-based data analytics to support large-scale monitoring and risk assessment.

Conclusion

The Agilent 7850 ICP-MS, combined with HPLC-ICP-MS, provides a reliable, accurate, and high-throughput solution for measuring inorganic arsenic, cadmium, lead and mercury in complex baby food matrices. The system meets stringent detection limits, quality control requirements, and supports compliance with emerging US legislation.

References

1. US House of Representatives Committee on Oversight and Reform, Baby Foods Are Tainted with Dangerous Levels of Arsenic, Lead, Cadmium, and Mercury, Feb 2021.
2. US House of Representatives, The Baby Food Safety Act of 2021.
3. FDA Center for Food Safety and Applied Nutrition, Inorganic Arsenic in Rice Cereals for Infants: Action Level Guidance for Industry, Aug 2020.
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5. FDA Arsenic in Rice and Rice Products Risk Assessment Report, 2016.
6. FDA, Closer to Zero: Action Plan for Baby Foods, Apr 2021.
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