COMPARATIVE SPECTROPHOTOMETRIC AND TITRIMETRIC ANALYSIS OF ASCORBIC ACID CONTENT IN NATURAL AND PHARMACEUTICAL SOURCES
Abstract
Background: Accurate determination of ascorbic acid (vitamin C) in foods and pharmaceuticals is essential for nutritional labeling and quality control. Traditional titrimetric methods are simple but may lack sensitivity, while spectrophotometric methods offer potential advantages. Objective: To compare titrimetric and UV-Vis spectrophotometric methods for quantifying ascorbic acid in natural (orange, bush mango) and pharmaceutical (50 mg tablets) sources. Methods: Fresh orange (Citrus sinensis) and bush mango (Irvingia gabonensis) fruits were extracted using 3% metaphosphoric acid. Tablet solutions were prepared by dissolving crushed tablets in distilled water. Titrimetric analysis used standardized 2,6-dichlorophenolindophenol (DCPIP) dye with endpoint detection by persistent pink color. Spectrophotometric analysis measured absorbance at 520 nm after reaction with DCPIP, using a calibration curve (R² = 0.9998). All samples were analyzed in triplicate. Results: Titrimetry gave ascorbic acid contents of 55.02 mg/100g (orange), 32.32 mg/100g (bush mango), and 46.01 mg/tablet. Spectrophotometry gave 58.00 mg/100g (orange), 34.20 mg/100g (bush mango), and 48.00 mg/tablet. Oranges contained approximately 70% more vitamin C than bush mangoes. The pharmaceutical tablet showed 8% lower content than the label claim (50 mg). Conclusion: UV-Vis spectrophotometry is superior to titrimetry in sensitivity, precision, and reproducibility for ascorbic acid determination. Oranges are richer sources of vitamin C than bush mangoes, but both fruits contribute meaningfully to dietary intake.
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