Analysis of Heavy Metals in Baby Food Using ICP-MS

Importance of the topic

Babies and infants are particularly susceptible to adverse health effects from trace and toxic metals. Reliable, sensitive and robust analytical methods for determining heavy metals in baby food matrices are essential to ensure compliance with evolving regulatory limits (US Baby Food Safety Act 2021 and recent EU limits) and to protect public health. Accurate measurement is also required to support risk assessment, product development and quality assurance in the food industry.

Objectives and study overview

This study evaluated an ICP‑MS workflow for multi‑element analysis of baby foods using the Shimadzu ICPMS‑2040/2050. Goals were to demonstrate method sensitivity relative to regulatory limits, assess matrix effects using spike recovery tests, evaluate carryover control strategies, and verify long‑term analytical stability during extended sample sequences. Five commercial baby food types with varied matrices were analyzed: infant formula, rice cereal, strained corn, strained pumpkin & sweet potato, and apple jelly.

Methodology

• Sample set: infant formula, rice cereal, strained corn, strained pumpkin & sweet potato, apple jelly.
• Sample preparation: approximately 0.5 g of sample was digested with 4 mL HNO3, 1 mL H2O2 and 0.5 mL HCl in closed vessels; microwave digestion at 200 °C for 20 minutes. After cooling, digests were diluted to 25 mL (~50× dilution).
• Analytical targets: thirteen elements including regulated analytes As (total As reported), Cd, Pb, Hg, Ni, Sn, plus Cr, Mn, Cu, Zn, Se, Mo, Tl.
• Carryover control: two rinse solutions were evaluated — pure water (Rinse 1) and an acid rinse (Rinse 2: 8% HNO3, 2% HCl v/v). Rinse 2 was applied selectively after high‑concentration samples by LabSolutions ICPMS to reduce carryover. ProActive Rinsing (initiating rinse during measurement) was used to shorten overall sequence time while maintaining cleanliness.
• Quality control: spike recovery tests (fortified samples) and sequence QC checks including Initial Calibration Verification (ICV), multiple Continuing Calibration Verifications (CCVs) and Continuing Calibration Blanks (CCBs) were used to assess accuracy and stability. Acceptance criteria followed FDA EAM 4.7 guidelines.

Instrumention used

• ICP‑MS: Shimadzu ICPMS‑2040/2050.
• Microwave digestion system for closed‑vessel acid digestions (200 °C, 20 min).
• Sample introduction: standard nebulizer/torpedo/sample introduction system with proactive rinsing capability.
• Gas and operating settings reported included RF power 1.20 kW, sampling depth 5 mm, pump speed 15 rpm, plasma gas ~9.0 L/min, auxiliary gas ~1.10 L/min, carrier gas ~0.45 L/min, dilution gas ~0.40 L/min, and He cell gas for collision mode where applicable.
• Internal standards deployed (e.g., 71Ga, 128Te, 193Ir) and helium collision gas to control interferences.

Main results and discussion

• Sensitivity and detection limits: Instrument detection limits were sufficiently low to meet stringent regulatory requirements, including limits for inorganic arsenic under the Baby Food Safety Act and recent EU regulations.
• Carryover mitigation: Adding the acid rinse (Rinse 2) for 240 s substantially reduced carryover compared with water only; for Se and Hg carryover was reduced to below detection limits. ProActive Rinsing further reduced total sequence time by overlapping rinse and measurement steps while maintaining low carryover.
• Accuracy (spike recovery): Spike recovery tests across the five matrices produced recoveries in the 88–110% range for all elements and samples, inside the FDA EAM 4.7 acceptance window (80–120%). This indicates effective matrix compensation and digestion performance across diverse baby food types.
• Long‑term stability: A continuous run of 50 infant formula samples (~6 hours) showed stable performance. ICV and CCV recoveries remained within 90–110% and CCB results were consistently below reporting limits, demonstrating analytical robustness for extended sequences and high‑matrix samples.
• Quantitative findings: Element concentrations varied markedly with matrix. Several elements (e.g., Zn, Cu) showed higher concentrations in some formulations, while toxic elements (As, Cd, Pb, Hg) were generally measured at low levels; the method provided quantitation well below regulatory maxima. No systemic failures or QC breaches were reported in the study summary.

Benefits and practical applications

• The described protocol combines closed‑vessel microwave digestion with ICP‑MS detection to deliver low detection limits, good accuracy across challenging matrices, and long‑term stability suitable for routine monitoring.
• ProActive Rinsing and selective acid rinses minimize carryover and reduce instrument downtime, improving throughput for high‑volume testing laboratories.
• Method aligns with regulatory QA/QC expectations (FDA EAM 4.7) and supports compliance testing required by recent US and EU regulations on toxic metals in baby foods.
• Approach is applicable for industry QC, contract testing laboratories, and regulatory monitoring programs where trace‑level determination of toxic metals is required.

Future trends and potential applications

• Increased emphasis on speciation: differentiating inorganic arsenic from organic forms will become more widespread, requiring hyphenated techniques (e.g., HPLC‑ICP‑MS) for regulatory compliance.
• Automation and sample throughput: further integration of automated sample preparation and intelligent rinsing workflows will raise daily throughput while ensuring QC integrity.
• Interference management: continued optimization of collision/reaction cell methods and data processing algorithms will reduce matrix biases and improve detection in complex foods.
• Standardization and reference materials: development and wider use of matrix‑matched certified reference materials for baby foods will strengthen method validation and interlaboratory comparability.
• Regulatory evolution: as limits evolve, methods will need to maintain or improve sensitivity and robustness, particularly for low‑level inorganic As and Ni monitoring.

Conclusion

The ICP‑MS method implemented on the Shimadzu ICPMS‑2040/2050, combined with microwave digestion and selective acid rinsing (plus ProActive Rinsing), provided sensitive, accurate and stable multi‑element analysis across diverse baby food matrices. Spike recoveries and long‑term QC demonstrated method validity for routine regulatory testing. The approach is fit for purpose for laboratories tasked with compliance testing against current US and EU limits and offers practical gains in throughput and carryover control.

Reference

• US House of Representatives. The Baby Food Safety Act of 2021. Accessed Jan 2026.
• European Commission. Commission Regulation (EU) 2023/915 of 25 April 2023 on maximum levels for certain contaminants in food and repealing Regulation (EC) No 1881/2006.
• European Commission. Commission Regulation (EU) 2024/1987 of 30 July 2024 amending Regulation (EU) 2023/915 as regards maximum levels of nickel in certain foodstuffs.