The Migration of Elements from Toys and Speciation of Chromium (VI) in Toy Material Using a Low Cost IC-ICP-MS Solution

Importance of the Topic

The accurate determination of hexavalent chromium in toy materials is critical for assessing health risks associated with carcinogenic Cr(VI) migration under regulatory limits. Speciation differentiates toxic Cr(VI) from essential Cr(III) and supports compliance with EU toy safety directives while protecting consumer safety.

Study Objectives and Overview

This study evaluates a low‐cost ion chromatography (IC)–ICP‐MS approach for simultaneous total elemental quantification and Cr(VI) speciation in toy extracts generated by migration tests per EN 71-3. It aims to achieve detection limits at single‐digit ng·L⁻¹ levels and assess method accuracy and precision across different toy matrices.

Methodology and Instrumentation

Sample extracts (finger paint, pen ink, TiO₂ pigment) underwent migration in acidic medium followed by stabilization via pH adjustment with NH₄OH to prevent Cr(VI) reduction. Total elemental analysis was performed on a Thermo Scientific iCAP Qc ICP‐MS operating in He KED mode with online internal standards (Ga, Rh, Ir). Speciation used a Thermo Scientific ICS-900 IC system with Dionex NG-1 guard and AG-7 anion exchange columns, coupled directly to the ICP‐MS via a PFA-LC nebulizer, avoiding metallic contamination and organic eluents.

Main Results and Discussion

Total element recoveries for spiked finger paint ranged from 94 % to 103 % for elements including Cr, Al, Zn, and Pb. The Cr(VI) detection limit was 0.9 ng·L⁻¹, with calibration linear from 0.05 to 4 ng·mL⁻¹. Untreated migration extracts contained no detectable Cr species; spiked Cr(VI) recoveries in migration solutions were between 88 % and 110 %, demonstrating stability over 24 h. Chromatograms achieved clear separation of Cr(VI) peaks from the column void volume, confirming method specificity.

Benefits and Practical Applications

• High sensitivity and low detection limits enable compliance with stringent EU toy safety limits.
• Metal‐free IC system and dilute nitric acid eluent eliminate carbon‐based spectral interferences.
• Single instrumental configuration supports both total elemental and speciation analyses, improving laboratory efficiency and throughput.

Future Trends and Applications

Further developments could include automated pH stabilization, expanded speciation of additional toxic metals in consumer products, and integration with high‐throughput workflows to address evolving regulations and real‐time quality control in toy manufacturing.

Conclusion

The combined IC‐ICP‐MS solution provides a robust, sensitive, and cost‐effective platform for trace elemental and Cr(VI) speciation in toys. It ensures accurate risk assessment and regulatory compliance while streamlining analytical workflows.

Reference

• European Standard EN 71-3:2012, Migration of certain elements.
• Thermo Scientific Application Note AN 43098, Chromium Speciation by IC-ICP-MS.