Using triple quadrupole ICP-MS to improve the speed, sensitivity, and accuracy of the analysis of toxic and nutritional elements in baby foods

Significance of the topic

Monitoring essential nutritional elements and potential toxic contaminants in baby foods is critical to protect vulnerable infant populations. Infants and young children require precise dietary intake of macro- and micronutrients while being susceptible to adverse effects from heavy metals even at trace levels. Regulatory bodies worldwide set stringent limits for elemental composition in infant foods, driving the need for analytical methods that deliver rapid, sensitive, and accurate results.

Objectives and study overview

This study aimed to demonstrate a streamlined approach using triple quadrupole ICP-MS to quantify both nutritional (major and trace) elements at mg·kg-1 levels and toxic elements at µg·kg-1 levels in various baby food matrices. The method integrates discreet sample valve automation for high throughput and reliable single-run analysis of up to 30 elements.

Methodology and instrumentation

An iCAP TQe triple quadrupole ICP-MS (Thermo Scientific) coupled with a CETAC ASX-560 autosampler and ASXpress Rapid Sample Introduction System was employed. Samples (milk powders, cereals, purees, juices) underwent acid microwave digestion, followed by aqueous dilution. Oxygen was used as the sole collision/reaction cell gas in TQ-O2 mode to remove polyatomic interferences. Calibration covered nine orders of magnitude using single-element standards in a 2% HNO3/HCl matrix, with online internal standards (Ga, In, Tb, Tl) added via the discreet valve. Sample throughputs of ~1 min 19 s per run, including repeats and rinsing, were achieved.

Main results and discussion

• Linearity and detection limits: Correlation coefficients (R²) > 0.999 for most analytes; method LOQs well below regulatory limits (e.g., As < 1.4 µg·kg-1, Cd < 1.1 µg·kg-1, Pb < 0.45 µg·kg-1).
• Accuracy: Recoveries for certified reference materials (NIST 2383a, BCR063, TYG082) ranged from 85 to 119 %. Pre-digestion spike recoveries (2 and 400 µg·kg-1) were between 80 and 125 %.
• Interference removal: TQ-O2 mode efficiently eliminated MoO+ and WO+ interferences on Cd and Hg, unlike conventional KED approaches, ensuring true quantitation in baby food matrices.
• Robustness: An 11-hour sequence of calibration checks, QC standards, real and simulated samples showed stable internal standard recoveries (75–110 %) and consistent CRM results.
• Real sample analysis: Thirty elements were quantified across ten baby food products, revealing broad concentration ranges (e.g., Ca 61–5512 mg·kg-1, Pb < 0.09–6.22 µg·kg-1) and demonstrating compliance assessment capabilities.

Benefits and practical applications

This single-run method simplifies multi-element analysis, reduces sample turnaround, and enhances laboratory throughput while meeting stringent regulatory requirements for baby food safety. The approach supports routine QA/QC protocols with automated calibration verification and spike recovery checks.

Future trends and potential applications

As global regulations for toxic element limits become more restrictive, the described TQ-ICP-MS method—coupled with advanced automation—offers adaptability for monitoring ultra-trace contaminants. Potential extensions include other complex food matrices, environmental samples, and high-throughput screening in regulatory and industrial laboratories.

Conclusion

The Thermo Scientific iCAP TQe ICP-MS in TQ-O2 mode, combined with CETAC ASXpress automation, enables rapid, sensitive, and accurate multi-element analysis of baby foods in a single measurement. The method's robustness, interference removal capability, and high throughput make it well-suited for ensuring nutritional quality and safety compliance.

Used instrumentation

Thermo Scientific iCAP TQe triple quadrupole ICP-MS; CETAC ASX-560 autosampler; ASXpress Rapid Sample Introduction System; Ethos microwave digestion; Qtegra ISDS Software.

References

1. Regulation (EU) No 609/2013 on food intended for infants and young children.
2. Grandjean P., Landrigan P.J., Lancet Neurol. 2014;13(3):330–8.
3. Federal Food, Drug and Cosmetic Act (FDCA), US.
4. GB-2762-2017 National Food Safety Standard, China.
5. Commission Regulation (EC) No 1881/2006 setting maximum levels for contaminants in foodstuffs.
6. Baby Food Safety Act of 2021, S.1019, 117th Congress.
7. Vincent T., Thermo Scientific Application Note 43446.
8. Smart Note 000214 on interference removal in ICP-MS.