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A new method of indirect determination of ascorbic acid(Vc) with ammonium sulfate and isopropyl alcohol by extraction-flotation of copper is studied in this paper. It shows that a small amount of Cu(Ⅱ) can be reduced to Cu( Ⅰ ) by Vc, then Cu(Ⅰ) reacted with the SCN-, which precipitated on the interface of isopropyl alcohol and H2O. A good linear relationship is observed between the flotation yield(E) of Cu( Ⅱ) and the amount of Vc. The detection limit for Vc is 1.76μg/mL. The method is simple, rapid (5 min), but suffers from little interference of common anions and cations. It has been successfully applied for the determination of Vc in fruits.
A new method of indirect determination of ascorbic acid (Vc) with ammonium sulfate and isopropyl alcohol by extraction-flotation of copper is studied in this paper. It shows that a small amount of Cu (II) can be reduced to Cu (I) by Vc, then Cu (I) reacted with the SCN-, which precipitated on the interface of isopropyl alcohol and H2O. A good linear relationship is observed between the flotation yield (E) of Cu (II) and the amount of Vc. The detection limit for Vc is 1.76 μg / mL. The method is simple, rapid (5 min), but suffers from little interference of common anions and cations. It has been successfully applied for the determination of Vc in fruits.