异Vc和Vc水溶液稳定性的比较研究

将Vc和异Vc配成水溶液，利用碘量法测定在不同时间、不同条件下它们的浓度，通过比较保存率，考察了水溶液pH值、金属离子和金属络合剂、光、水质、食盐和温度等因素对它们稳定性的影响。试验所表现出的总体规律是：相同条件下，Vc比异Vc更稳定。

STABILITY COMPARISON OF D-ISOASCORBIC ACID AND L-ASCORBIC ACID IN AQUEOUS SOLUTION

This paper focuses on the stability of L-ascorbic acid and D-isoascorbic acid influenced by the factors such as PH value, metallic ion and metallic ion chelating reagent, light and water quality, table salt and temperature. The results show that D-isoascorbic acid at PH 3.5 is more unstable than at PH 6.86 or PH 9.18. D- isoascorbic acid kept away from light becomes more stable than exported to light. At the same time, D-isoascorbic acid dissolved in running water becomes more unstable than in de-ionized water. Metallic ion can damage D- isoascorbic acid, while metallic chelating reagent can protect it. Table salt has protective action to D-isoascorbic acid. D-isoascorbic acid becomes more and more unstable as the temperature increases. Under the same conditions, L-ascorbic acid is more stable than D-isoascorbic acid.