Overview - ISO 15192:2021 (Soil and waste, Chromium(VI) determination)
ISO 15192:2021 specifies a validated laboratory procedure for the determination of Chromium(VI) / Cr(VI) in solid waste materials and soils. The method uses an alkaline digestion to extract Cr(VI) from solid matrices, followed by ion chromatography (IC) separation and spectrophotometric detection. It is applicable to Cr(VI) mass fractions in solids greater than 0.1 mg/kg. Note: results are not valid for strongly reducing or oxidising waste matrices.
Key topics and technical requirements
- Extraction principle: alkaline digestion designed to solubilize Cr(VI) while minimizing reduction to Cr(III) or oxidation of Cr(III) to Cr(VI). Addition of Mg in a phosphate buffer reduces air oxidation during digestion.
- Separation and detection:
- Ion chromatography to separate chromate from interferences.
- Detection options: direct UV at 365 nm or post‑column derivatisation with 1,5‑diphenylcarbazide and VIS detection at 540 nm (post‑column is more sensitive).
- Hyphenated detectors (e.g., ICP‑MS, ICP‑AES) may be used after proper validation.
- Performance and limits: intended for Cr(VI) > 0.1 mg/kg; attention to column capacity (e.g., high chloride may cause underestimation).
- Apparatus & consumables: 250 mL digestion vessels with thermostatic heating and stirring (hotplate or heating block), 0.45 µm membrane filters, IC column suitable for chromate, inert flow-path materials (e.g., PEEK).
- Reagents & water quality: analytical grade reagents; ultrapure water recommended (≈18 MΩ·cm). Reagents listed include concentrated H2SO4, anhydrous Na2CO3, and high‑purity 1,5‑diphenylcarbazide.
- Quality control: calibration, blanks, duplicate samples, spiked soluble Cr(VI) and Cr(III) checks, and method verification procedures are required to ensure reliable results.
- Safety: Cr(VI) compounds are genotoxic and potentially carcinogenic - strict handling controls and national regulations must be followed.
Practical applications and users
- Environmental and analytical laboratories performing contaminated land assessments, waste characterization, remediation monitoring, and regulatory compliance testing.
- Waste treatment facilities and consultants needing reliable Cr(VI) speciation in solids.
- Regulatory bodies and accreditation labs applying ISO/IEC 17025 for validated methods.
- Researchers studying chromium mobility, speciation and risk assessment in soils and solid wastes.
Related standards
- ISO 8466-1 (method calibration & evaluation)
- ISO 11464 (sample pretreatment)
- ISO 11465 (dry matter determination)
- ISO/IEC 17025 (laboratory competence)
- EN 15002, EN 15934 (waste/sample preparation and dry matter calculation)
Keywords: ISO 15192:2021, Chromium(VI), Cr(VI) determination, alkaline digestion, ion chromatography, spectrophotometric detection, soil and waste analysis, environmental laboratory.