Ensuring toy safety from hexavalent chromium to meet European regulations using IC-ICPMS quantification

Importance of the Topic

The presence of hexavalent chromium in toys poses serious health risks, especially to children who may ingest small components. European regulations (EN 71-3:2019) enforce strict migration limits for Cr(VI). Reliable detection at ultra-low levels is crucial to protect consumers and ensure regulatory compliance.

Objectives and Overview of the Study

This study aimed to refine an existing ion chromatography–ICP-MS (IC-ICPMS) workflow to quantify Cr(VI) migration from sticky or liquid toy materials (category II) and scraped-off materials (category III). Key goals were compliance with EN 71-3:2019, a quantification limit down to 0.0025 mg/kg in toys, and a robust migration test protocol.

Methodology and Instrumentation

Samples and migration extracts were prepared following EN 71-3 guidelines under alkaline conditions to stabilize Cr(VI). Separation was achieved on a dual-column setup (IonPac NG1 guard + AG7 analytical) using 75 mM HNO₃ at pH 7.0, with standards adjusted to pH 7.5. The IC effluent was directly introduced into a Thermo Scientific iCAP RQ ICP-MS via a PFA-LC nebulizer. The 52Cr isotope was monitored in helium collision mode (KED) to eliminate interferences. A multi-pump configuration and an AS-AP autosampler allowed rapid sequential injections.

Used Instrumentation

• Thermo Scientific Dionex ICS-6000 ion chromatography system
• Thermo Scientific iCAP RQ ICP-MS
• Thermo Scientific Dionex AS-AP autosampler
• IonPac NG1 and AG7 columns
• PFA-LC Nebulizer

Main Results and Discussion

Calibration over 0.02–0.16 µg/L Cr(VI) exhibited excellent linearity (R² = 0.9998) and a background-equivalent concentration of 0.002 µg/L. The instrumental detection limit was 0.35 ng/L, corresponding to 0.0025 mg/kg in toys—twenty-times below the regulatory threshold. Migration testing of glue, paint, and plastic extracts showed no native Cr(VI). Spiked samples (0.01 µg/L) yielded recoveries of 98–109% with stable retention times (~50 s) and no carry-over. Analysis time was reduced to 2 min per run.

Benefits and Practical Application of the Method

• Meets stringent regulatory limits for toy safety
• High-throughput, rapid analysis for QA/QC labs
• Robust separation of Cr species without interconversion
• Minimal sample preparation and carry-over risk

Future Trends and Potential Applications

As regulations evolve, detection limits may need further reduction. Coupling with high-resolution mass analyzers or advanced chromatographic phases could enhance sensitivity. Automation of migration procedures and data processing will streamline lab workflows and support routine screening.

Conclusion

The optimized IC-ICPMS method delivers a fast, reliable, and ultra-sensitive approach for Cr(VI) quantification in toys, ensuring compliance with current EN 71-3:2019 standards and readiness for future regulatory demands.

Reference

1. EN 71-3:2019 Safety of Toys – Part 3: Migration of certain elements
2. Alvarez CC, Gómez MEB, Zavala AH. Hexavalent chromium: Regulation and health effects. Journal of Trace Elements in Medicine and Biology, 2021.
3. Thermo Fisher Scientific Application Note 43175