Stability and transformation of products formed from dimeric dehydroascorbic acid at low pH

► Dehydroascorbic acid dimer is the commercially available form of oxidised vitamin C. ► Dissolution at pH below four results in the formation of hydrated dimeric products. ► Products are interconvertible and are only partially transformed into vitamin C. ► Two hydrated products are sufficiently stable to be identified at neutral pH. ► Relevance: Analysis of vitamin C and studies of dehydroascorbic acid uptake.