Stable, Convenient-working Extractants for the Determination of L-ascorbic Acid in Citrus Extracts

As an effort to find a more stable, convenient-working extractant than regularly used methaphosphoric acid for determination of L-ascorbic acid (AA) in citrus extracts, several extractants for assay of AA were examined. The extractants tested were (I) 15 g stick HPO.,+ 40 ml acetate+450 ml H,O, (II) 0.5% stick HPO,+O.Z% Oxalate+HJO, (III) 0.2% Oxalate+5% Acetate+H,O, (IV) 0.2% Oxalate+ 10% Acetate+H,O, (V) 7% Citrate+0.5% Malate+H?O. Based on measurements of AA stored in the extractants and AA content in the juice of Citrus limon Burm. cv. Frost Nucellar Lisbon, the combinations of oxalate plus acetate resulted in more convenient, less expensive and more stable extractants.