ISO 23821:2022 PDF

Overview

ISO 23821:2022 - Cosmetics - Analytical methods - Determination of traces of mercury in cosmetics by atomic absorption spectrometry (AAS) cold vapour technology after pressure digestion provides a validated laboratory procedure for quantifying mercury in finished cosmetic products. The method combines pressure (microwave-assisted) digestion with cold vapour AAS (optionally using amalgam concentration) to achieve trace-level determination suitable for regulatory and quality-control testing.

Key technical topics and requirements

• Scope and principle
  • Applicable to finished cosmetic products; digestion in closed vessels under pressure and heat (microwave-assisted) followed by cold vapour AAS measurement.
  • Measurement at the mercury atomic absorption line 253.7 nm; reduction of Hg(II) to elemental mercury using reducing agents.
• Sample preparation
  • Pressure digestion (microwave) at temperatures up to ~200 °C and pressures up to ~40 bar using mineral acids (nitric and hydrochloric).
  • Filtration (membrane filter 0.45 µm) and preparation of measurement solutions with controlled acid content.
• Reagents
  • Nitric acid, hydrochloric acid (stabilization recommended ≈ 1% HCl in solutions), reducing agents such as tin(II) chloride or sodium borohydride (freshly prepared; NaBH4 requires strict ventilation due to H2 evolution).
  • Use certified mercury stock standards and matching acid-stabilized calibration solutions; prepare fresh daily.
• Instrumentation and cleaning
  • Cold vapour AAS systems with cold vapour or amalgam (gold/platinum mesh) accessories; flow-injection alternatives supported.
  • Rigorous decontamination of glassware (acid washes, ultrapure water) and use of low-contamination materials (borosilicate/quartz).
• Quality control and performance
  • Calibration blanks, multiple calibration points, daily standard preparation.
  • The standard includes procedures for limit of quantification (LOQ) assessment, quality control, and method reliability; method performance was validated by interlaboratory testing (ISO 5725 approach) and compared with ISO 23674.

Practical applications and users

• Laboratories performing cosmetic safety testing and compliance checks for mercury contamination.
• Manufacturers and quality-control teams verifying raw materials and finished products.
• Regulatory agencies and accredited testing bodies enforcing limits for mercury in cosmetics.
• Research labs conducting elemental analysis of cosmetic matrices.

Related standards

• ISO 23674 (parallel method; interlaboratory comparison documented)
• ISO 3696 (water for analytical laboratory use)
• ISO 5725 (statistical methods for method validation)

Keywords: ISO 23821:2022, mercury in cosmetics, cold vapour AAS, pressure digestion, microwave digestion, cosmetic testing, trace mercury analysis.