Trace elemental analysis of chicken egg using Shimadzu Inductively Coupled Plasma-Mass Spectrometer (ICP-MS)

Importance of the Topic

Eggs serve as a rich source of high quality proteins, lipids, vitamins and essential minerals. Monitoring trace elements in eggs is critical for food safety and nutritional quality. While minerals like Se, Zn and Cu are vital at dietary levels, excessive accumulation of toxic elements such as As, Cd or Pb can pose health risks. Variability in poultry feed and environmental contamination further underscores the need for reliable analytical methods to quantify elemental content in egg matrix.

Objectives and Study Overview

The present study aimed to develop and validate a robust protocol for trace element quantitation in chicken eggs using Shimadzu ICPMS-2030. Target elements were selected in line with FSSAI maximum residual limits. Key goals included establishing method sensitivity down to 20% of the regulatory limits, assessing repeatability and accuracy through spike recovery tests, and verifying instrumental stability via continuous calibration checks.

Methods and Instrumentation

Sample Preparation:

• Approximately 500 mg of homogenized egg sample underwent microwave digestion with 5 mL suprapure nitric acid, 0.5 mL hydrogen peroxide and 1 mL ultrapure water.
• Digestion program: Ramp to 120 C in 10 min (hold 5 min), then to 180 C in 10 min (hold 30 min).
• Post digestion, samples were cooled, made up to 50 mL, and spiked at LOQ and 10 times LOQ levels for recovery assessment.

Calibration:

• Standards were prepared from 1000 ppm certified solutions covering 10 to 250 percent of FSSAI limits.
• LOQs were set at 20 percent of MRLs per EU regulation 836 2011.

Instrumentation:

• Analyzer: Shimadzu ICPMS-2030 with AS-10 autosampler
• Internal standards: Bi, Ge and Y
• Plasma torch: mini torch, RF power 1.2 kW, sampling depth 5 mm
• Gas flows: plasma 10 L min, auxiliary 1.1 L min, carrier 0.7 L min, collision (He) 6.0 mL min
• Chamber: cyclone type at 5 C

Key Results and Discussion

Calibration curves for all elements exhibited excellent linearity with correlation coefficients r ≥ 0.999. Measured concentrations in egg samples were below instrument LOQs. Spike recovery at LOQ and 10× LOQ ranged between 80 and 120 percent, with relative standard deviations below 8 percent, demonstrating high repeatability. Continuous calibration verification showed accuracy between 90 and 110 percent, confirming instrumental stability throughout the analytical run.

Benefits and Practical Applications

This method provides a fast and reliable approach for trace element analysis in complex biological matrices. High spike recoveries and low RSD values ensure confidence in results, making it suitable for routine food safety testing, quality control in egg production, and regulatory compliance monitoring.

Future Trends and Opportunities

Advancements may include coupling ICP-MS with separation techniques for speciation analysis, automation of sample preparation for higher throughput, adoption of greener digestion reagents, and extension of the protocol to other food and environmental samples to broaden its applicability.

Conclusion

The developed microwave digestion and ICP-MS protocol meets regulatory requirements for trace element determination in chicken eggs. Validation data confirm its accuracy, precision and robustness, positioning the method as a reliable tool for food safety laboratories.

References

1. Food Safety and Standards (Contaminants, Toxins and Residues) Regulations 2006
2. Food Safety and Standards (Contaminants, Toxins and Residues) Regulations 2011
3. Commission Regulation EU No 836/2011