AOAC SPIFAN Stakeholder Program Meeting Book (September 10, 2020)

Analytical methods III

HPLC based methods

Based on an acidic extraction followed by chromatographic separation of ascorbic acid (or dehydroascorbic acid)

D-isoascorbic is separated from L-ascorbic acid by chromatography.

Standard solution: 2 — g/mL ascorbic acid

Sample solution: 80 mg ascorbic acid/100 g

Advantages: clear identification of the compounds and separation from interferences, includes dehydroascorbic acid if appropriate sample preparation.

Disadvantages: requires HPLC trained staff and equipment, longer analysis time than titration

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Source of illustrations Lemons: https://www.savibio.fr/fruits/42-citron-jaune.html

Sample portion considerations

SPIFAN recommendations for powdered infant formulas and adult/pediatric formulas

25 g of sample (serving size) to be reconstituted to «as-consumed» by dissolution in 200 g of water

When expanding to other matrixes such as processed cereal-based foods, homogeneity of the samples becomes specially important.

Critical to ensure sample homogeneity by proper grinding of a representative sample portion

25-50 g recommended as representative sample portion after homogeneization of larger sample weight

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Source of illustrations Lemons: https://www.savibio.fr/fruits/42-citron-jaune.html