Dehydroascorbic acid undergoes hydrolysis on solubilization which can be reversed with mercaptoethanol

Using gas chromatography-mass spectrometry, we have examined the effect of solubilization, cupric sulfate oxidation and mercaptoethanol reduction of dehydroascorbic acid. During solubilization, dehydroascorbic acid spontaneously hydrolyzed the lactone ring. The reduction of the dehydroascorbic acid hydrolysis product using mercaptoethanol resulted in the formation of ascorbic acid, suggesting that sulfhydryls are able to effect ring closure of the dehydroascorbic acid hydrolysis product. These data suggest that studies of dehydroascorbic acid should be interpreted with caution, since properties attributed to dehydroascorbic acid may actually be due to another chemical species.