Analysis of Nutritional and Harmful Elements in Powdered Milk by ICPE-9820 / HVG-1

Importance of the Topic

The balanced intake of essential minerals such as calcium, iron, and copper is vital for infant development, while monitoring toxic elements like arsenic is crucial for safety. Regulatory guidelines mandate accurate labeling of mineral content and strict control of harmful contaminants in powdered infant formula. High-sensitivity analytical methods enable manufacturers and regulators to verify compliance and protect infant health.

Objectives and Study Overview

This study aimed to demonstrate simultaneous quantification of both nutritional minerals and trace toxic elements in powdered milk using the Shimadzu ICPE-9820 ICP atomic emission spectrometer and the HVG-1 hydride vapor generator. Certified reference material (NMIJ CRM 7512-a) was analyzed to evaluate method accuracy, detection limits, and measurement stability.

Instrumentation Used

• Shimadzu ICPE-9820 simultaneous ICP atomic emission spectrometer with automatic axial/radial observation switching for high-concentration and trace-level elements.
• HVG-1 hydride vapor generator for enhanced arsenic detection at ng/L levels.

Methodology and Sample Preparation

Ultrasonic microwave digestion was applied to 0.5 g powdered milk samples using a mixture of nitric acid, hydrochloric acid, hydrogen peroxide, and perchloric acid to ensure complete decomposition. Yttrium and indium internal standards were added to the digested solution. For arsenic analysis, samples were heated near dryness and treated with hydrochloric acid, potassium iodide, and ascorbic acid before hydride generation.

Key Results and Discussion

• Major minerals (Ca, K, Na, Mg, P) measured by radial and axial ICP detection fell within certified reference values, with expanded uncertainties under 5 %.
• Trace elements (Cd, Cr, Pb) showed recovery rates around 98–100 % and detection limits below 0.002 mg/L in measurement solution.
• Arsenic analysis using HVG-1 achieved a detection limit of 0.04 µg/L in solution (2 µg/kg in powder) and a 99 % recovery for a 4 µg/L spike.
• Continuous monitoring of a 1 µg/L arsenic standard over four hours yielded an RSD of 1.6 %, indicating excellent long-term stability.

Benefits and Practical Applications

The combined use of axial and radial observation in ICPE-9820 allows simultaneous measurement of elements across a broad concentration range without multiple instrument setups. The HVG-1 adds high-sensitivity arsenic analysis, supporting quality control, regulatory compliance, and risk assessment in infant formula production.

Future Trends and Potential Applications

• Integration of automation for sample digestion and hydride generation to increase throughput in quality assurance laboratories.
• Enhanced detection systems for other hydride-forming elements (e.g., selenium, antimony) to broaden application scope.
• Development of real-time monitoring workflows for inline analysis during manufacturing.

Conclusion

Simultaneous ICP-AES analysis with the ICPE-9820, combined with HVG-1 for arsenic, provides a robust, sensitive, and efficient platform for comprehensive elemental profiling of powdered milk. The method meets regulatory requirements and offers reliable performance for both high-concentration nutrients and trace contaminants.

References

• Allowable Standard for Component Composition and Display of Breast Milk and Infant Formula, Ministry of Health, Labour and Welfare, Japan.