Overview
EN ISO 23821:2022 specifies an analytical method for the determination of traces of mercury in cosmetics using cold vapour atomic absorption spectrometry (AAS) after pressure (closed-vessel) digestion. Prepared by ISO/TC 217 in collaboration with CEN/TC 392 and adopted as a European standard, this method describes sample digestion, instrumental setup and quality-control measures for reliable mercury quantification in finished cosmetic products.
Key topics and technical requirements
- Scope: Determination of mercury in cosmetic matrices by cold vapour AAS following pressure-assisted digestion.
- Sample digestion: Closed-vessel pressure digestion (microwave-assisted) at elevated temperature (document notes digestion at about 200 °C) to mineralize cosmetics prior to measurement.
- Detector technique: Cold vapour AAS with reduction of Hg(II) (examples: tin(II) chloride or sodium borohydride) and transfer of mercury vapor to the AAS cuvette.
- Pre-concentration: Optional use of gold/platinum amalgam (mesh) to concentrate mercury and achieve lower limits of quantification (LOQs).
- Reagents and water quality: Use of analytical-grade acids (e.g., HCl 30%, HNO3 65%), reducing agents and water conforming to ISO 3696 Grade 1.
- Quality control and validation: Method performance validated by interlaboratory testing (ISO 5725 approach) on cosmetic matrices (e.g., lipstick, lotion, toothpaste, eyeshadow) across mercury levels reported in the standard (approx. 0.110 mg/kg to 5.84 mg/kg). The standard includes procedures for calibration, blanks, and reporting.
- Documentation: Prescribed test report items and calculation/evaluation steps including LOQ determination and reliability assessment.
Applications and users
This standard is intended for:
- Cosmetic testing laboratories performing routine and regulatory analyses for mercury content.
- Quality control (QC) teams in cosmetics manufacturing verifying product safety.
- Regulatory authorities and conformity assessors enforcing chemical safety requirements in cosmetics.
- Research laboratories studying contaminant occurrence or method performance in cosmetic matrices.
Practical benefits:
- Standardized, traceable procedure for accurate mercury quantification.
- Compatibility with common laboratory equipment (microwave digestion, cold vapour AAS systems).
- Guidance for achieving low LOQs suitable for regulatory compliance and safety risk assessment.
Related standards
- ISO 23674 - parallel method development referenced in the standard’s validation context.
- ISO 5725 - statistical approach for interlaboratory validation and performance assessment.
- ISO 3696 - specification for laboratory water quality used in reagent preparation.
Keywords: EN ISO 23821:2022, mercury in cosmetics, cold vapour AAS, pressure digestion, mercury determination, cosmetics testing, analytical methods.