Chemiluminometric determination of ascorbic acid in pharmaceutical formulations exploiting photo-activation of GSH-capped CdTe quantum dots

Author(s)

Sasaki, M. K. ^[1] ; Ribeiro, D. S. M. ^[2] ; Frigerio, C. ^[2] ; Prior, J. A. V. ^[2] ; Santos, J. L. M. ^[2] ; Zagatto, E. A. G. ^[1]

Affiliation

^[1] Univ Sao Paulo, NAPTISA Ctr Nucl Energy Agr, Piracicabe - Brazil

^[2] Univ Porto, Fac Pharm, REQUIMTE Dept Chem Sci, P-4100 Oporto - Portugal

• Document type: Journal article
• Source: LUMINESCENCE; v. 29, n. 7, p. 901-907, NOV 2014.
• Web of Science Citations: 7

Abstract

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 x 10(-7) to 5.0 x 10(-6) mol/L ascorbic acid (r = 0.9967, n = 5) was attained, with a detection limit of 3.05 x 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 (C) 2014 John Wiley \& Sons, Ltd. (AU)

• FAPESP's process: 11/14413-0 - Comparison of flow analyzers with laminar or pulsed flows and immobilized reagents: application to samples of pharmaceutical, agronomical and/or environmental relevance
• Grantee: Milton Katsumi Sasaki
• Support Opportunities: Scholarships in Brazil - Doctorate