Overview
EN ISO 21424:2020 (identical to ISO 21424:2018) defines an ICP‑MS method for the quantitative determination of a suite of minerals and trace elements in milk, milk products, infant formula and adult nutritional products. The standard covers sample digestion, instrument tuning, calibration and calculation procedures needed to measure Ca, Cu, Fe, Mg, Mn, P, K, Na, Zn, Cr, Mo and Se using inductively coupled plasma mass spectrometry (ICP‑MS). It is published by CEN as the European adoption of the ISO/IDF method.
Key topics and technical requirements
- Analytes covered: Calcium, copper, iron, magnesium, manganese, phosphorus, potassium, sodium, zinc, chromium, molybdenum and selenium.
- Applicable matrices: Infant formula and adult nutritionals (all 12 elements); milk, milk powder, whey powder, butter and cheese (all elements except chromium, which was below quantification limits in those matrices).
- Sample preparation: Closed‑vessel microwave digestion with nitric acid, an internal standard and hydrogen peroxide; digestion temperature is specified (200 °C in the method principle).
- ICP‑MS operation: Instrument tuning, use of internal standards, calibration standard sets, and autosampler rinse procedures are specified to control accuracy and contamination.
- Quality control and performance: The standard includes calibration blanks, preparation blanks, precision data (repeatability and reproducibility) and reporting requirements. Precision data and analytical ranges are provided in the standard (see Table 1 and Annex A of the document).
- Method lineage: The method extends earlier standards (ISO 20649 | IDF 235) and is equivalent to AOAC Official Method 2015.06 for infant formula minerals and trace elements.
Practical applications
- Routine quantitative analysis of minerals and trace elements for:
- Nutritional labeling and formulation verification (infant formula, adult nutritionals, dairy products)
- Quality control during production of milk‑based products
- Regulatory compliance and food safety monitoring for trace elements (e.g., Se, Mo, Cr)
- Multi‑element screening where high sensitivity and low detection limits are required; ICP‑MS offers rapid, simultaneous determination of the listed elements.
Who should use this standard
- Dairy and infant formula laboratories performing compositional analysis
- Food testing and public health laboratories monitoring mineral/trace element content
- Manufacturers of nutritional products and quality assurance teams
- Accreditation bodies and regulators specifying validated analytical methods
Related standards
- ISO 20649 | IDF 235 (earlier method, validated for Cr, Mo, Se in infant formula)
- AOAC Official Method 2015.06 (equivalent method for infant formula)
- Laboratory ISO/IEC accreditation guidance for analytical testing
For implementation, consult the full EN ISO 21424:2020 text for detailed procedures, reagent specifications, calibration ranges and precision tables.
