Overview
ISO 20634:2015 specifies a validated analytical method for the quantitative determination of vitamin B12 in infant formula and adult nutritionals (powders, ready‑to‑feed liquids and liquid concentrates) using reversed phase high performance liquid chromatography (RP‑HPLC). The method converts cobalamins to cyanocobalamin, uses solid‑phase extraction (C8 or C18) for cleanup and concentration, and detects vitamin B12 by visible absorption at 550 nm. ISO 20634:2015 is published by ISO in collaboration with AOAC and is equivalent to AOAC Official Method 2011.10.
Key topics and technical requirements
- Scope and sample types: powders, liquid concentrates and ready‑to‑feed liquids for infants and adults. Definitions reference Codex/food‑product standards.
- Principle: extraction with sodium acetate buffer (pH 4.5), conversion to cyanocobalamin with potassium cyanide at about 105 °C, SPE cleanup, size‑exclusion and reversed‑phase chromatography, visible detection at 550 nm.
- Reagents and mobile phases: analytical grade solvents (acetonitrile, triethylamine, formic acid), potassium cyanide solutions prepared fresh, and sodium acetate buffer (c = 0.25 mol/L, pH 4.5).
- HPLC system and columns: gradient pump with column switching, UV‑VIS detector (tungsten lamp), autosampler (large injection volumes), size‑exclusion and C18 reversed‑phase columns specified.
- Apparatus and sample prep: SPE cartridges (C8/C18), oven for controlled heating, pH meter, desiccator, laboratory light shields (UV protection), enzymatic treatment for starch‑containing products (Taka‑Diastase).
- Quality and calibration: preparation of stock/intermediate/calibration standards, resolution test solution (riboflavin), procedures for standard curves and calculations.
- Safety: method involves hazardous reagents (e.g., potassium cyanide) and high temperatures - appropriate safety/health practices required.
- Supporting information: Annexes include example chromatograms, precision data and an SPE cartridge qualification procedure.
Applications and who uses it
- Food testing laboratories performing routine and regulatory analysis of nutrient content in infant formula, pediatric and adult nutritional products.
- Manufacturers and quality control (QC) teams verifying product labeling and formulation targets for vitamin B12.
- Regulatory authorities and standards bodies assessing compliance with nutrient specifications.
- Method validation and R&D groups adapting or comparing analytical approaches for cobalamin analysis.
Practical benefits: reliable, reproducible quantification of vitamin B12 across product formats; defined sample preparation, cleanup and HPLC setup for consistent inter‑laboratory results.
Related standards
- Equivalent to AOAC Official Method 2011.10: Vitamin B12 in infant and pediatric formulas and adult nutritionals.
- Definitions reference Codex Standard 72‑1981 for infant formula.
Open preview (PDF)Infant formula and adult nutritionals — Determination of vitamin B12 by reversed phase high performance liquid chromatography (RP-HPLC)
