When determining TP of water using Phosphorus Molybdenum Blue Method, ascorbic acid solution was unstable, can only be kept for several weeks.

It reports that L-ascorbic acid's polarographic oxidation wave in acid solution and its application.

L-ascorbyl palmitate in the methanol extract is hydrolyzed under acid condition, and 2, 6-dichlorophenol indophenol sodium solution is titrated with the hydrolysate.