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Molecules 2016, 21(1), 101;

A New Indirect Spectrofluorimetric Method for Determination of Ascorbic Acid with 2,4,6-Tripyridyl-S-Triazine in Pharmaceutical Samples

Department of Chemistry, Faculty of Science, University of Sarajevo, Zmaja od Bosne 33-35, Sarajevo 71 000, Bosnia and Herzegovina
Faculty of Chemistry and Technology, University of Split, Teslina 10, Split 21 000, Croatia
These authors contributed equally to this work.
Author to whom correspondence should be addressed.
Academic Editor: Derek J. McPhee
Received: 6 October 2015 / Revised: 11 January 2016 / Accepted: 13 January 2016 / Published: 19 January 2016
(This article belongs to the Section Medicinal Chemistry)
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Ascorbic acid (AA) is a water-soluble vitamin which shows no fluorescence. However, in reaction with iron(III), AA is oxidised to dehydroascorbic acid and iron(III) is reduced to iron(II) which forms a complex with 2,4,6-tripyridyl-S-triazine (TPTZ) in buffered medium. The relative fluorescence intensity of the resulting Fe(TPTZ)22+ complex can be measured at excitation and emission wavelengths of 393 and 790 nm, respectively. Based on this data, a new indirect spectrofluorimetric method for the determination of AA in pharmaceutical samples was proposed. Influence of the reaction conditions, such as acidity of acetic buffer, concentration of TPTZ and iron(III), reaction time and instrumental parameters were investigated in detail. The linear range was from 5.4 × 10−4 to 5.4 × 10−6 mol·L−1 (R = 0.9971). The LOD was 7.7 × 10−7 mol·L−1 and LOQ was 2.3 × 10−4 mol·L−1. Fourteen pharmaceutical samples containing various amounts of AA were analysed. Influences of potential interfering substances were also examined. Analysis of commercial pharmaceutical formulations showed good correlation with the nominal values given by the manufacturers and with the results obtained by a titration method. The proposed method can be applied in routine quality control in the pharmaceutical industry due to its sensitivity, simplicity, selectivity and low cost. View Full-Text
Keywords: spectrofluorimetry; ascorbic acid; 2,4,6-tripyridyl-S-triazine spectrofluorimetry; ascorbic acid; 2,4,6-tripyridyl-S-triazine

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Klepo, L.; Copra-Janicijevic, A.; Kukoc-Modun, L. A New Indirect Spectrofluorimetric Method for Determination of Ascorbic Acid with 2,4,6-Tripyridyl-S-Triazine in Pharmaceutical Samples. Molecules 2016, 21, 101.

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