Determination of Nutrients and Micronutrients in Milk Powder and Infant Formula by ICP-OES

Significance of the Topic

Milk powder and infant formula provide essential fats, vitamins, minerals, and micronutrients for balanced nutrition and infant development. Ensuring accurate multi-element analysis is critical to meet stringent regulatory requirements and prevent contamination during processing. Inductively coupled plasma optical emission spectrometry (ICP-OES) offers higher throughput and lower detection limits than traditional FAAS methods, supporting efficient quality assurance in dairy manufacturing.

Objectives and Overview of the Study

This application note assesses the performance of the Agilent 5800 Vertical Dual View ICP-OES with an SPS 4 autosampler and smart software tools for quantifying calcium, copper, iron, potassium, magnesium, manganese, sodium, phosphorus, and zinc in milk powder and infant formula, in compliance with ISO 15151:2018.

Methodology

• Sample preparation: 1 g of sample predigested with 10 mL HNO3, then microwave-digested (1030–1800 W, 200 °C, 20–25 min ramp, 15 min hold) and diluted to 50 mL.
• Analysis parameters: Dual axial and radial views, Fitted Background Correction, internal standard yttrium (371.029 nm), three replicates, read times 10 s (axial) and 5 s (radial), sample uptake delay 16 s, rinse time 30 s, pump speed 12 rpm.

Instrumentation

Agilent 5800 VDV ICP-OES equipped with a SeaSpray nebulizer, double-pass glass cyclonic spray chamber, semi-demountable dual view torch (1.8 mm i.d.), and SPS 4 autosampler. Agilent ICP Expert software features IntelliQuant, IntelliQuant Screening, Early Maintenance Feedback (EMF), and Vista Chip III detector with FBC for background correction.

Main Results and Discussion

• Calibration and linearity: Correlation coefficients >0.99993 across all analyte wavelengths, exceeding ISO 15151 upper limits.
• Limits of quantification: LOQs substantially lower than ISO 15151 minimums (e.g., Ca 0.73 mg/kg vs 200 mg/kg, Cu 0.05 mg/kg vs 0.3 mg/kg).
• CRM recovery: Certified reference material MP-A recoveries were within ±10% of certified and reference values for all elements.
• IntelliQuant screening: Semiquantitative concentrations within ±14% of expected values, demonstrating real-time sample insight and optimal wavelength selection.
• Long-term stability: 250 digested samples analyzed over 11 h without recalibration; QC recoveries remained within ±10% and %RSD <0.9% for all elements.

Benefits and Practical Applications

• High throughput: Approximately 150 s per sample including automated internal standard addition.
• Smart quality assurance: IntelliQuant and EMF reduce remeasurements and downtime by verifying data quality and scheduling maintenance only when needed.
• Comprehensive analysis: Single-run measurement of macro- and micronutrients meets regulatory and industry demands.

Future Trends and Opportunities

Emerging trends include integration of AI-driven spectral deconvolution, expansion to diverse food matrices, remote instrument health monitoring, and enhanced semiquantitative screening databases to streamline method development and quality control workflows.

Conclusion

The Agilent 5800 VDV ICP-OES with SPS 4 autosampler and ICP Expert software meets ISO 15151:2018 requirements, offering accurate, precise, and robust multi-element analysis of milk powder and infant formula with minimal downtime and reduced reanalysis.

References

• ISO 15151:2018, Milk, milk products, infant formula and adult nutritionals — Determination of minerals and trace elements by ICP-AES.
• Agilent Technologies, ICP Expert software publications: 5994-1517EN, 5994-1516EN, 5994-1518EN.
• Chinese patent CN10223705, 2016, Method for determination of silicone oil leakage and freeze-drying end point.