Overview
ISO 20260:2019 specifies validated analytical methods for the determination of mercury in magnesium and magnesium alloys. It covers two quantitative techniques - inductively coupled plasma mass spectrometric analysis (ICP‑MS, Method A) and atomic absorption spectrometric analysis (AAS, Method B) - and defines sampling, sample handling, apparatus, reagents, operation, blank tests, calibration and reporting procedures for trace mercury measurement. The standard supports trace-level mercury control in magnesium products and aligns with global regulatory attention (e.g., the Minamata Convention).
Keywords: ISO 20260:2019, mercury determination, magnesium alloys, ICP‑MS, atomic absorption spectrometry, trace mercury.
Key topics and requirements
- Scope and methods
- Method A: ICP mass spectrometric analysis - applicable for mercury from 0.00001% to 0.01% (mass fraction).
- Method B: Atomic absorption spectrometric analysis - applicable for mercury from 0.00002% to 0.001% (mass fraction).
- Sampling & sample prep
- Chip sampling from castings or products, drilling at right angles, removing surface contamination, use of desiccator to cool chips.
- Prohibits oils/lubricants during drilling; remove ferrous contamination with a magnet.
- Storage & weighing
- Store analytical samples in hermetically sealed glass containers; clean surface contaminants (e.g., ethanol) before analysis.
- Typical sample masses: 0.1 g for ICP‑MS and 0.5 g for AAS, weighed to 1 mg resolution.
- Apparatus & glassware
- Class A volumetric glassware per ISO 384/648/1042 and tested per ISO 4787.
- Analytical balance sensitive to 0.1 mg, ICP‑MS and AAS instrumentation specified.
- Reagents & chemistry (examples from Method A)
- Use analytical‑grade acids and reagents and grade 1/2 water (ISO 3696).
- Specific reagents include potassium permanganate (to suppress Hg volatilization), nitric/hydrochloric acids, hydroxylamine hydrochloride (to reduce MnO2), L‑cysteine and calibration solutions (Mg, Al, Zn).
- Quality control
- Blank tests, working (calibration) curves, and detailed calculation/reporting rules are specified to ensure trace accuracy and reproducibility.
Applications and users
- Primary users
- Metallurgical and foundry quality control labs, third‑party testing laboratories, alloy manufacturers and suppliers.
- Use cases
- Routine QC for magnesium ingots, castings and wrought products to meet material specifications.
- Regulatory compliance and trade documentation where mercury limits are required (e.g., under the Minamata Convention).
- Research and development for new Mg alloys where trace impurities must be quantified.
- Benefits
- Standardized methodology for consistent, trace-level mercury measurement across suppliers and laboratories.
Related standards
This standard is essential for labs and manufacturers needing reliable, reproducible methods for mercury analysis in magnesium and magnesium alloys using ICP‑MS or AAS.