Abstract
We have designed a new chelating method for the determination of L-ascorbic acid (AsA) in plasma. For the blank, AsA is oxidized with L-ascorbate oxidase before deproteinization with trichloroacetic acid (TCA). During the reaction, iron (Fe3+) is reduced to Fe2+ with AsA, which can be continuously monitored by chelating Fe2+ and 2-nitroso-5-(N-propyl-N-sulfopropylamino)phenol. We determined the optimal concentrations of substrate and reactants and developed a method, to eliminate proteins in the plasma sample by treatment with TCA. Results from this method correlate well with the 2, 4, 6-tris-(2-pyridyl)-s-triazine method for determination. We established a reference interval of 10-450μM; and at optimal conditions within this range, the variance of this method was less than 1.50%.
