Overview
EN ISO 20647:2020 (identical to ISO 20647:2015 / IDF 234:2015) specifies a validated laboratory method for the quantitative determination of total iodine in infant formula and adult nutritional products using inductively coupled plasma mass spectrometry (ICP‑MS). The method covers powdered, reconstituted and ready‑to‑feed products and was developed through interlaboratory evaluation. It is also equivalent to AOAC Official Method 2012.15.
Key topics and technical requirements
- Scope and measurement range
- Reconstituted final product: 0.5 µg/100 g to 1 500 µg/100 g
- Ready‑to‑feed products: 2.5 µg/100 g to 1 000 µg/100 g
- Interlaboratory study results reported between 3.47 µg/100 g and 124 µg/100 g
- Analytical principle
- Sample digestion with potassium hydroxide (KOH) in an oven or open‑vessel microwave
- Iodine stabilization after digestion using ammonium hydroxide and sodium thiosulfate
- Filtration, appropriate dilution and determination by ICP‑MS
- Reagents and materials
- High‑purity reagents (KOH, NH4OH, Na2S2O3, concentrated HNO3, HClO4), surfactant (e.g., Triton X‑100), and purified water (18 MΩ·cm)
- Note: KOH and other reagents can contribute background iodine; use certified analytical grades
- Quality and performance
- Calibration, conditioning and data acceptability criteria are defined
- Precision (repeatability and reproducibility) established via an interlaboratory study; full precision data available in Annex A (Table A.1)
- Safety
- Standard warns about hazardous materials and procedures; laboratories must follow appropriate safety and regulatory controls
Applications and users
This standard is designed for:
- Food testing laboratories performing regulatory compliance testing for iodine content
- Infant formula and adult nutritional product manufacturers for product development, QC and label verification
- Regulatory agencies and food safety authorities assessing nutrient labelling and public health requirements
- Contract testing and R&D labs using ICP‑MS for trace element analysis
Practical benefits include reproducible, traceable results across labs and direct applicability to powdered and ready‑to‑feed nutritionals.
Related standards
- ISO 20647:2015 / IDF 234:2015 (original international text)
- EN ISO 20647:2020 (CEN adoption for European national standards)
- AOAC Official Method 2012.15 (equivalent method for total iodine in formula)
For method implementation, consult the full standard for detailed procedures, calibration and precision tables (Annex A) and follow laboratory safety and accreditation requirements.