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Abstract
Vitamin C (ascorbic acid) is an essential water-soluble vitamin with antioxidant and physiological functions. This study comparatively determined the vitamin C content of selected commercial tablet and syrup formulations and of mango and African star apple using iodometric titration and UV–visible spectrophotometry. Two tablet formulations, two syrups and the two fruits were analysed in triplicate. The UV–visible method was calibrated with standard ascorbic acid solutions and gave a linear curve (R² = 0.9996). By iodometry, Tablet A and Tablet B contained 482.50 ± 4.91 and 499.20 ± 5.89 mg/tablet; the corresponding UV–visible values were 489.20 ± 7.41 and 503.70 ± 6.13 mg/tablet. Syrup A and Syrup B contained 98.40 ± 2.39 and 92.70 ± 1.91 mg/5 mL by iodometry, and 99.10 ± 2.40 and 93.60 ± 1.82 mg/5 mL by UV–visible analysis. Mango contained 28.60 ± 0.71 mg/100 g by iodometry and 29.45 ± 0.83 mg/100 g by UV–visible analysis; African star apple contained 42.35 ± 0.91 and 43.20 ± 0.96 mg/100 g. African star apple contained more vitamin C than mango. Tablet formulations were close to their declared label claims. Percentage differences between the two methods ranged from 0.71% to 2.93%. Both methods were suitable for quantitative determination of vitamin C. Mango and African star apple remain useful natural sources of the vitamin.