Titrimetric determination of vitamin C in natural and commerical fruit juice samples using a locally extracted dye

F.U. Willie And A. S. Ekop*

Department of Chemistry, University of Uyo, p.m.b 1017, uyo, (Nigeria)

ABSTRACT: An alternative method has been developed for accurate determination of vitamin C in various juice samples using aqueous extract of fresh exoderm of fluted pumpkin seeds. This locally extracted dye (LED) gives a better percentage recovery by titration method when compared to the conventional titrimetric method using 2,6 - Dichlorophenol-indophenol (DCPIP). Student’s t-test statistical analysis for correlated paired data showed that there is no significant difference (a = 0.01, N = 21) in precision and reproducibility in the determination by both the new LED and conventional DCPIP methods. Vitamin C content of 21 samples including natural fruits, commercial fruit juice and vitamin C tablets have been accurately determined using this method. The method developed has also been successfully adapted to spectrophotometric titration for determination of trace amount (<0.064mg/ml) of vitamin C in fruit juice samples.

KEYWORDS: Vitamin C; Determination; Titrimetric method; Local Dye Extract (LED)

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