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close this bookScurvy and its Prevention and Control in Major Emergencies (WHO; 1999; 70 pages)
View the documentAcknowledgements
View the documentScurvy: definition
open this folder and view contentsIntroduction
open this folder and view contentsScurvy
close this folderVitamin C
View the documentDiscovery
close this folderProperties
View the documentChemistry
View the documentPhysiology
View the documentMetabolic functions
View the documentUse of vitamin C
open this folder and view contentsRecommended Daily Allowance (RDA)
open this folder and view contentsSources of vitamin C
open this folder and view contentsStrategies to prevent scurvy in large refugee populations
View the documentCosts
open this folder and view contentsConclusions and recommendations
View the documentReferences
View the documentAnnex 1
View the documentAnnex 2
View the documentAnnex 3
View the documentBack Cover
 

Chemistry

L-ascorbic acid, which is often equated with vitamin C (Marks, 1975), has much in common with its precursor, D-glucose. The empiric formula is C6H8O6, and in its pure form it is a white odourless, crystalline substance with a melting point of 192°C. It is a very powerful reducing agent, reducing silver nitrate, potassium permanganate, iodine, and many organic substances. It is freely soluble in water, slightly soluble in ethanol, and quite insoluble in most non-polar lipid solvents. In crystalline form, kept dry and not exposed to light, it is stable for a considerable length of time. In an aqueous solution it is attacked by atmospheric oxygen, other oxidizing agents, high pH, high temperature and metallic ions.

L-ascorbic acid is reversibly converted to dehydroascorbic acid, which together constitute the active form of vitamin C (Hodges, 1980). Dehydroascorbic acid can be oxidized further both rapidly and irreversibly at a pH above 4 where traces of heavy metal ions, e.g. copper, act as catalysts. The end products are oxalic acid and L-threonic acid.

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