The skeletal structure of an aldonic acid, gluconic acid (top), and its aldose, glucose (bottom).
Aldonic acids are sugar acids with the general chemical formula, HO2C(CHOH)nCH2OH. They are obtained by oxidizing the aldehyde (-CHO group) of an aldose to form a carboxylic acid (-COOH group).[1] Aldonic acids are generally found in their ring form. However, these rings do not have a chiral carbon at the terminal end bearing the aldehyde, and they cannot form R−O−R′ linkages between different molecules.[2]
The nomenclature of aldonic acids and their lactones is based on replacing the suffix "-ose" with "onic acid" or "onolactone". Hence, D-glucose is oxidized to D-gluconic acid and D-gluconolactone.[3]