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Chemiluminometric determination of ascorbic acid in pharmaceutical formulations exploiting photo‐activation of GSH‐capped CdTe quantum dots
Author(s) -
Sasaki M. K.,
Ribeiro D. S. M.,
Frigerio C.,
Prior J. A. V.,
Santos J. L. M.,
Zagatto E. A. G.
Publication year - 2014
Publication title -
luminescence
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.428
H-Index - 45
eISSN - 1522-7243
pISSN - 1522-7235
DOI - 10.1002/bio.2639
Subject(s) - ascorbic acid , chemiluminescence , chemistry , cadmium telluride photovoltaics , quantum dot , combinatorial chemistry , chromatography , nanotechnology , materials science , food science
An automated multi‐pumping flow system is proposed for the chemiluminometric determination of ascorbic acid in pharmaceutical formulations, relying on the ability of semiconductor nanocrystals to generate short‐lived reactive species upon photo‐irradiation. A photo‐unit based on visible‐light‐emitting diodes is used to photo‐excite cadmium telluride (CdTe) quantum dots capped with glutathione, leading to the generation of radicals that react with luminol under alkaline conditions, yielding the chemiluminescence. Ascorbic acid acts as a radical scavenger, preventing the oxidation of luminol, thus ensuring a concentration‐dependent chemiluminescence quenching. After system optimization, a linear working range of 5.0 × 10 ‐7 to 5.0 × 10 ‐6 mol/L ascorbic acid ( r = 0.9967, n = 5) was attained, with a detection limit of 3.05 × 10 ‐7 mol/L and a sampling rate of 200/h. The flow system was applied to the analysis of pharmaceutical formulations and the results were in good agreement with those obtained by the reference titrimetric procedure (RD < ± 4.3%, n = 7). Copyright © 2014 John Wiley & Sons, Ltd.