Overview
ISO 20633:2015 specifies a validated analytical method for the simultaneous quantitative determination of vitamin E and vitamin A in infant formula and adult nutritionals using normal phase high performance liquid chromatography (HPLC). The scope covers powdered formulas, ready‑to‑feed liquids and liquid concentrates. The method is equivalent to AOAC Official Method 2012.10 and is intended for routine laboratory testing, regulatory compliance and quality control.
Key topics and technical requirements
- Analytes covered: α‑tocopherol and α‑tocopheryl acetate (vitamin E); 13‑cis and all‑trans retinyl palmitate and retinyl acetate (vitamin A). Retinol is not addressed. Stereoisomers of vitamin E are not differentiated.
- Sample types: Dry blended powders, wet blended powders, liquid concentrates and ready‑to‑feed liquids.
- Sample preparation principle: Proteolytic digestion (papain) to hydrolyze protein coatings, followed by single‑step extraction of lipophilic vitamins into iso‑octane.
- Chromatography: Normal‑phase HPLC with gradient elution. Detection uses fluorescence for vitamin E (excitation 280 nm, emission 310 nm) and UV for vitamin A (325 nm).
- Standards and calibration: Preparation of stock and combined working standard solutions with multipoint calibration curves (6‑point typical; 3–4 points acceptable for routine ranges). Procedures for spectrometric and chromatographic purity checks of standards are specified.
- Reagents and apparatus: HPLC‑grade solvents (iso‑octane, n‑hexane, methyl‑t‑butyl ether, methanol), papain enzyme, antioxidants (e.g., hydroquinone) and HPLC system with appropriate detectors.
- Quality controls: System suitability checks, precision data (annex), and examples of chromatograms provided in the standard.
- Safety note: Method uses hazardous solvents and reagents; laboratories must apply appropriate health and safety practices.
Applications and users
ISO 20633:2015 is practical for:
- Food and beverage analytical laboratories performing nutritional labeling verification.
- Infant formula and adult nutritional manufacturers for product development, batch release and stability testing.
- Regulatory and accreditation bodies requiring standardized methods to check fortification levels of vitamins A and E.
- Contract testing labs and research groups measuring fat‑soluble vitamin content in complex matrices.
Keywords: ISO 20633:2015, infant formula analysis, adult nutritionals, vitamin E determination, vitamin A HPLC, normal phase HPLC, α‑tocopherol, retinyl palmitate, nutritional testing.
Related standards
- Equivalent AOAC method: AOAC 2012.10 (method equivalence noted in the ISO foreword).
- Comparative references included in ISO 20633 annexes: EN 12822 and EN 12823‑1 (comparative information provided).
Open preview (PDF)Infant formula and adult nutritionals — Determination of vitamin E and vitamin A by normal phase high performance liquid chromatography
