Simple and Sensitivity Spectrophotometric Analytical Method for Ascorbic Acid Determination in Vegetables, Fruits, and Different Pharmacological Models

Abstract

Abstract

Within the present study, ascorbic acid was estimated based on a simple and fast reaction with a distinctive sensitivity based on an oxidation and reduction reaction in the presence of a mixture of iron(III) ions and reagent 1,10-phenanthroline in an acidic medium. The measurements were made at the wavelength of the greatest absorption of 510 nm, and the reaction included two basic stages: The first stage was the oxidation of ascorbic acid in an acidic medium in the presence of iron (III) ions. When the ion reduces to an iron (II) ion, 1,10-phenanthroline reacts with the iron (II) ion in a second stage to form a red complex. In the study, the optimal conditions for the reaction were determined, including the acidity function, the type of buffer solution, the concentration of iron(III) ions, the concentration of 1,10-phenanthroline if it was 5, citric solution as a buffer solution, 10-6 and 10-4 mol/L, respectively, and the volume of iron(III) ions, 1,10 reagent-phenanthroline, hydrochloric acid, and ascorbic acid was 4, 2.5, 1 and 0.5 ml, respectively. A calibration curve was prepared in the optimal conditions and had a linear range ranging from 0.5 to 10 mg/L and a correlation coefficient of 0.996, and then a negative deviation occurred. The analytical method under study was applied to determine ascorbic acid in different models, including vegetables and fruits, and different pharmacological models to determine the method's accuracy by calculating the recovery ratio