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

Importance of the Topic

Food safety monitoring increasingly relies on speciation analysis to distinguish toxic forms of elements from less harmful ones. Hexavalent chromium and inorganic arsenic species pose significant health risks, and their accurate quantification in food products and packaging materials is crucial for regulatory compliance and consumer protection.

Objectives and Study Overview

This work presents the development and validation of coupled liquid chromatography–inductively coupled plasma mass spectrometry (LC-ICPMS) methods for the quantification of Cr(III)/Cr(VI) in packaging materials and As(III), As(V) and dimethylarsenic acid in rice. The goal is to achieve fast, sensitive, and robust analysis that meets EU regulatory limits.

Methodology and Instrumentation

Instrumentation Used:

• Shimadzu ICPMS-2030 with Minitorch plasma source
• Shimadzu Prominence Inert HPLC system

Chromatographic Conditions:

• Chromium speciation: Hamilton PRP-X100 column, 30 mM ammonium nitrate buffer at pH 7.1, 495 µL injection volume
• Arsenic speciation: Shiseido Capcell Pak C18 MG S5 column, ion-pair mobile phase containing 10 mM sodium 1-butanesulfonate, 4 mM tetramethylammonium hydroxide, 4 mM malonic acid (pH 3), 0.05 % methanol, 20 µL injection volume

ICP-MS Operating Parameters:

• RF power 1.2 kW, plasma gas 8 L/min, auxiliary gas 1.1 L/min, carrier gas 0.6 L/min
• Collision cell helium gas flow 6 mL/min, cell voltage –21 V, energy filter 7 V
• Argon consumption below 10 L/min with 99.95 % purity

Main Results and Discussion

Chromium species were baseline separated and calibrated over a low-ppt range with correlation coefficients above 0.9999. The method complies with the EU VerpackV limit of 100 mg/kg for Cr(VI) in packaging. Arsenic speciation achieved separation of As(III), As(V) and DMAA in under 5 minutes. Analysis of NMIJ CRM 7503-a (white rice) yielded total inorganic arsenic at 0.0852 mg/kg and CRM 7532-a (brown rice) at 0.302 mg/kg, in excellent agreement with certified values and RSDs below 3 %.

Benefits and Practical Applications

The combined LC-ICPMS approach offers rapid throughput, high sensitivity and selectivity, and streamlined data processing for routine quality control in food safety and packaging surveillance. Single-platform software simplifies method development and compliance reporting.

Future Trends and Opportunities

Advances may include expanding speciation to other toxic metals such as mercury and antimony, integrating high-resolution mass analyzers, developing miniaturized plasma sources to reduce gas consumption, and automating sample preparation for high-throughput laboratories.

Conclusion

LC-ICPMS using Shimadzu instrumentation provides a reliable, sensitive and efficient solution for chromium and arsenic speciation in food and packaging, supporting regulatory compliance and consumer safety.

References

• Commission Regulation (EU) 2015/1006 on maximum levels of inorganic arsenic in foodstuffs
• VerpackV Ordinance 2014 on the avoidance and recovery of packaging wastes
• NMIJ Certified Reference Materials CRM 7503-a and CRM 7532-a