Measurement of traces of heavy metals in cosmetic raw materials and finished products according to ISO/DIS 21392:2021 using triple quadrupole ICP-MS

Significance of the Topic

The rapid expansion of the global cosmetics market has heightened concerns about trace levels of heavy metals that can pose health risks to consumers. Regulatory frameworks such as EU Regulation EC 1223/2009 set maximum allowable limits for chromium, lead, arsenic, cadmium and mercury in cosmetic products. Reliable analytical methods are essential to verify compliance and guarantee product safety.

Study Objectives and Overview

This application note describes a complete workflow for quantifying trace heavy metals in both cosmetic raw materials and finished products in accordance with ISO DIS 21392 2021. It emphasizes the use of triple quadrupole inductively coupled plasma mass spectrometry to remove isobaric and polyatomic interferences and to achieve low quantification limits.

Methodology and Instrumentation

A microwave assisted acid digestion protocol was applied using an ultraWAVE single reaction chamber system combined with an EasyFILL acid dispenser for reproducible sample preparation. Analysis was carried out on a Thermo Scientific iCAP MTX triple quadrupole ICP MS with an iSC 65 autosampler. Argon gas dilution was employed to handle high total dissolved solids. The QCell was operated in both collision mode with helium gas and reaction mode using oxygen to eliminate interferences. Calibration spanned 0.5 to 10 micrograms per liter for most elements, with higher ranges for Al Ti and Fe. Internal standards (Ge Rh In Lu Ir) were added online to correct for matrix effects.

Main Results and Discussion

Internal standard signals remained stable within 80 to 110 percent over analysis of more than 120 samples demonstrating high robustness. Analytical figures of merit including correlation coefficients above 0.998, blank equivalent concentrations below 1 microgram per kilogram and method quantification limits compliant with ISO requirements were obtained for 19 elements. In samples containing tungsten and zirconium, reaction mode (TQ O2) completely removed tungsten oxide interferences on mercury and zirconium oxide overlaps on cadmium, whereas collision mode (KED) produced significant overestimation of these analytes. Spike recovery tests across diverse cosmetic matrices yielded results within the 70 to 150 percent range specified by ISO DIS 21392.

Benefits and Practical Applications of the Method

• Comprehensive detection of regulated and emerging elements in cosmetics
• Effective interference removal by triple quadrupole reaction mode ensures accurate trace level quantification
• Automated acid digestion and dilution streamline workflows and improve reproducibility
• Full compliance with ISO DIS 21392 2021 and EU cosmetic regulations enhances consumer safety

Future Trends and Applications

Demand for high throughput and reliable heavy metal testing in cosmetics will drive wider adoption of triple quadrupole ICP MS platforms. Integration of remote diagnostics automated maintenance assistants and advanced reaction cell chemistries may further improve laboratory productivity and detection capabilities. The approach can be extended to other complex matrices where isobaric and polyatomic interferences challenge accurate quantification.

Conclusion

The presented workflow combining microwave assisted digestion argon gas dilution and triple quadrupole ICP MS with oxygen reaction mode fulfills ISO DIS 21392 2021 requirements. It delivers robust interference elimination low quantification limits and high sample throughput for both cosmetic raw materials and finished products ensuring adherence to strict safety regulations.

Reference

1. Regulation EC 1223 2009 on Cosmetic Products
2. ISO DIS 21392 2021 Cosmetics Analytical Methods
3. Milestone Srl UltraWAVE Single Reaction Chamber Technology 2021