Exploitation of a simple redox reaction between manganese(III) and o-tolidine for a highly sensitive spectrophotometric determination of ascorbic acid.

Abdul Galil, and Yogendra Kumar, M. S. and Sathisha, M. A. and Suresh, M. S. and Gowtham, M. D. and Vijaya Bhaskar, C. and Nagendrappa, G. (2007) Exploitation of a simple redox reaction between manganese(III) and o-tolidine for a highly sensitive spectrophotometric determination of ascorbic acid. Analytical Chemistry: An Indian Journal, 6 (2, Cop). pp. 70-74.

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Abstract

A simple and highly sensitive spectrophotometric method for the detn. of ascorbic acid is described. The developed method is based on a redox reaction in that Mn(III) generated electrolytically is taken in excess, which is oxidizing a known but a less quantity of vitamin C and the unreacted oxidant will oxidize further o-tolidine to produce a orange yellow quinonediimine absorbing cation (λmax. 455 nm). Therefore, in principle, the decrease in color intensity of the absorbing system is proportional to the concn. of vitamin C. The stoichiometry between Mn(III) and o-tolidine and stability of the complex were detd. by Job's method, the corresponding values obtained were 2:1 and 1.58 × 105 L mol-1. The system is obeying Lambert-Beer's law in the range, 0.08-0.8 mg L-1 of ascorbic acid. Molar absorptivity, correlation coeff., and Sandell's sensitivity values were also calcd. and are 4.4359 × 103 0.9987 and 0.0397 μg/cm-2, resp. The reliability of the new method was tested by parallel detn. of ascorbic acid in std., pharmaceutical and fruit samples using a std. method. The results of vitamin C obtained from both the methods were comparable with one another and the reliability and reproducibility of the new method were concluded by F and t test values. Therefore, the new method could be employed effectively for the detn. of ascorbic acid in std. and other samples either as an independent high sensitive spectrophotometric method or a complimentary method to official method. [on SciFinder(R)]

Item Type: Article
Additional Information: Unmapped bibliographic data: PY - 2007/// [EPrints field already has value set] JA - Anal. Chem.: Indian J. [Field not mapped to EPrints]
Uncontrolled Keywords: ascorbic acid detn spectrophotometry trivalent manganese tolidine redox reaction
Subjects: Physical Sciences > Chemistry
Divisions: PG Campuses > Manasagangotri, Mysore > Chemistry
Depositing User: Dhruvakumar
Date Deposited: 11 Jun 2013 10:07
Last Modified: 30 Nov 2015 07:48
URI: http://eprints.uni-mysore.ac.in/id/eprint/12380

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