MEASURING MAJOR AND MINOR ELEMENTS IN MILK USING THE AGILENT MP-AES 4200

Significance of the Topic

Accurate quantification of major and minor elements in milk is vital for assessing product quality and nutritional value. Traditional sample digestion is time-consuming and uses hazardous reagents. A direct dilution approach with MP-AES offers a faster, safer routine analysis.

Objectives and Study Overview

This study evaluates the Agilent MP-AES 4200 combined with flow blurring nebulization for determining Ca, K, Mg, Na, P, Fe, Zn and Cu in a skim milk powder reference material. Accuracy, precision and stability are assessed against certified values.

Methodology and Instrumentation

• Sample preparation: 0.5 g milk powder diluted in TMAH, Triton X-100, EDTA and CsNO3 solution; ultrasonic mixing.
• Instrument: Agilent MP-AES 4200 with OneNeb nebulizer, cyclonic spray chamber, easy-fit torch and SPS-3 autosampler.
• Analytical conditions: selected emission lines free from spectral interference, CsNO3 suppressor for ionization correction, nitrogen generator for plasma.

Main Results and Discussion

All measured element concentrations agreed within 5 % of certified values. Stability over two hours yielded RSDs between 0.7 % (K) and 2.8 % (Mg). The method demonstrated robust plasma performance and eliminated the need for flammable gases.

Benefits and Practical Applications

• Rapid direct analysis without acid digestion or ashing.
• High precision and accuracy suitable for routine QA/QC.
• Reduced reagent hazards and operational costs.

Future Trends and Opportunities

Expansion to other dairy matrices and complex food samples, integration with automation and hyphenated techniques, ongoing improvements in nebulization and matrix tolerance to broaden application scope.

Conclusion

The Agilent MP-AES 4200 with flow blurring nebulization offers a simple, reliable and cost-effective method for routine determination of key elements in milk, delivering accurate results and stable long-term performance.

Reference

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3. S. E. Emmet. Analysis of liquid milk by inductively coupled plasma mass spectrometry. Journal of Analytical Atomic Spectrometry. 1988;3:1145–1146.
4. M. A. Aguirre et al. Compensation for matrix effects on ICP-OES by on-line calibration with flow blurring nebulizer. Journal of Analytical Atomic Spectrometry. 2010;25:1724–1732.
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