Overview
ISO 23674:2022 - Cosmetics - Analytical methods - Direct determination of traces of mercury in cosmetics by thermal decomposition and atomic absorption spectrometry (mercury analyser) specifies a validated, direct solid‑analysis procedure to quantify trace mercury in finished cosmetic products. The method measures total mercury (inorganic + organic) in either solid or liquid cosmetics without prior chemical digestion, using thermal decomposition followed by atomic absorption spectrometry (mercury analyser). It is intended to assess mercury exposure risk from consumer use.
Keywords: ISO 23674:2022, mercury in cosmetics, mercury analyser, thermal decomposition, atomic absorption spectrometry, trace mercury, cosmetic safety testing.
Key Topics and Requirements
- Principle: Samples are thermally decomposed (combustion at ~650–900 °C) in an oxygen flow. Combustion gases pass a catalyst (~615 °C), mercury vapour is trapped on a gold amalgamator, then desorbed (≈800–900 °C) and measured at the 253.7 nm mercury absorption line.
- Scope: Direct determination in finished cosmetic products; applicable to solids and liquids; no sample digestion required.
- Reagents & Materials: Ultrapure water (ISO 3696 Grade 1), diluted HCl or HNO3 (with optional L‑cysteine), certified mercury stock solutions for calibration.
- Apparatus: Elemental mercury analyser (commercial “mercury analysers”), compatible sample boats/containers (e.g., nickel, quartz, ceramic). Typical sample capacities ~500 mg (solid) or 500–1 500 µl (liquid).
- Calibration: Minimum of five calibration standards across expected concentration range; calibration may use liquid or solid standards; strategies provided for concentration/volume-based calibration.
- Quality Control: Includes analysis blanks, QC samples, and replicates. Cleaning procedures (acid rinses) to minimize contamination are required.
- Performance & Reporting: Method performance, validation/validated ranges and accuracy-profile data are addressed; test report requirements are specified.
Practical Applications and Users
- Cosmetic product manufacturers implementing raw-material and finished-product quality control.
- Third‑party analytical and conformity testing laboratories performing safety compliance tests.
- Regulatory authorities and market surveillance bodies verifying limits on mercury in cosmetics.
- Accreditation bodies and laboratory managers developing validated test methods consistent with ISO requirements.
- Health and safety teams assessing consumer exposure to trace mercury from cosmetic use.
Benefits: rapid, direct analysis without digestion, element‑specific sensitivity, reduced matrix interferences, and suitability for routine screening and regulatory compliance.
Related Standards (if applicable)
- ISO 23821 (developed in parallel; interlaboratory comparison performed)
- ISO 3696 - Water for analytical laboratory use (referenced for ultrapure water quality)
- Prepared by ISO/TC 217 (Cosmetics)
For labs seeking practical implementation: follow instrument manufacturer guidance, adhere to the QC procedures in ISO 23674:2022, and consult ISO 23821 when comparing alternate mercury determination workflows.
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