Quantitative Analysis of Chromium and Arsenic Species in Food and Food Packaging using LC-ICPMS

Importance of the Topic

Food safety is a critical public health priority across Europe. Monitoring not only total elemental levels but also specific chemical species of toxic elements such as chromium and arsenic provides deeper insight into their true toxicological impact. Speciation analysis enables regulators and industry to distinguish between relatively benign and highly harmful forms, ensuring compliance with legislation and protection of human and environmental health.

Objectives and Study Overview

This study demonstrates the application of liquid chromatography coupled with inductively coupled plasma mass spectrometry (LC-ICPMS) to quantify hexavalent chromium in food packaging materials and inorganic arsenic species in rice. It addresses the need for reliable, sensitive methods that meet European regulatory limits and support farm-to-fork safety controls.

Used Instrumentation

• Shimadzu ICPMS-2030 with Minitorch setup (low argon flow, high sensitivity)
• Shimadzu Prominence Inert LC System for separation of metal species

Methodology

Chromium Speciation in Packaging:

• Sample introduction via low-flow Ar plasma (<10 L/min, 99.95% purity)
• Ion-exchange LC separation of Cr(III) and Cr(VI)
• ICPMS detection with collision cell (He gas) to minimize interferences
• Calibration achieved linear response over low ppt range (r>0.9999)

Arsenic Speciation in Rice:

• Ion-pair chromatography to resolve As(III), As(V) and dimethylarsinic acid (DMAA) within 5 min
• ICPMS quantification against certified reference materials
• Recovery and precision validated using NMIJ CRM for white and brown rice

Key Results and Discussion

Chromium:

• Excellent sensitivity enabled quantitation of Cr(VI) below regulatory limit (100 mg/kg total heavy metals in packaging)
• Calibration curves demonstrated outstanding linearity and low detection limits

Arsenic:

• Total inorganic arsenic in white and brown rice measured at 0.0852 mg/kg and 0.302 mg/kg respectively, in agreement with certified values
• RSD values below 3% confirmed robustness of the method

Benefits and Practical Applications

The combined LC-ICPMS approach offers:

• High throughput routine analysis on a single software platform
• Compliance with EU regulations for packaging wastes and maximum arsenic levels in rice
• Capability to distinguish toxic species from less harmful forms, improving risk assessment

Future Trends and Opportunities

Ongoing advancements may include:

• Automation and miniaturization of LC-ICPMS systems for in-line process monitoring
• Expanded speciation panels covering additional metal species and organic contaminants
• Integration with high-resolution mass analyzers to further reduce detection limits and interferences

Conclusion

LC-ICPMS proves to be a powerful and versatile analytical platform for the accurate speciation of chromium in packaging materials and arsenic in rice. The methods described deliver fast, reliable results that meet stringent regulatory demands, while offering detailed toxicological insights essential for safeguarding public health.

References

1. Lab Manager. Gluten-free diet may increase risk of arsenic, mercury exposure. (2017).
2. Verpackungsverordnung (VerpackV). Ordinance on the Avoidance and Recovery of Packaging Wastes (2014).
3. Ricepedia. The global staple rice consumers. (2017).
4. Commission Regulation (EU) 2015/1006, amending Regulation (EC) No 1881/2006 on maximum levels of inorganic arsenic in foodstuffs.