Photoactivation by visible light of CdTe quantum dots for inline generation of reactive oxygen species in an automated multipumping flow system.
Quantum dots (QD) are semiconductor nanocrystals able to generate free radical species upon exposure to an electromagnetic radiation, usually in the ultraviolet wavelength range. In this work, CdTe QD were used as highly reactive oxygen species (ROS) generators for the control of pharmaceutical formulations containing epinephrine. The developed approach was based on the chemiluminometric monitoring of the quenching effect of epinephrine on the oxidation of luminol by the produced ROS. Due to the relatively low energy band-gap of this chalcogenide a high power visible light emitting diode (LED) lamp was used as photoirradiation element and assembled in a laboratory-made photocatalytic unit. Owing to the very short lifetime of ROS and to ensure both reproducible generation and time-controlled reaction implementation and development, all reactional processes were implemented inline by using an automated multipumping micro-flow system. A linear working range for epinephrine concentration of up to 2.28×10(-6) mol L(-1) (r=0.9953; n=5) was verified. The determination rate was about 79 determinations per hour and the detection limit was about 8.69×10(-8) mol L(-1). The results obtained in the analysis of epinephrine pharmaceutical formulations by using the proposed methodology were in good agreement with those furnished by the reference procedure, with relative deviations lower than 4.80%.
Requimte, Department of Chemical Sciences, Laboratory of Applied Chemistry, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira no. 228, 4050-313 Porto, Portugal.
David S M
DS
Ribeiro
Christian
C
Frigerio
João L M
JL
Santos
João A V
JA
Prior
D000975:Antioxidants / Q000032:analysis; D001993:Bronchodilator Agents / Q000032:analysis*; D019187:Cadmium Compounds / Q000737:chemistry*; D004837:Epinephrine / Q000032:analysis*; D004867:Equipment Design; D008027:Light; D057230:Limit of Detection; D049408:Luminescent Agents / Q000737:chemistry; D008163:Luminescent Measurements / Q000295:instrumentation / Q000379:methods*; D008165:Luminol / Q000737:chemistry; D010084:Oxidation-Reduction; D004364:Pharmaceutical Preparations / Q000737:chemistry; D055668:Photochemical Processes; D045663:Quantum Dots; D017382:Reactive Oxygen Species / Q000737:chemistry*; D013691:Tellurium / Q000737:chemistry*
D000975:Antioxidants; D001993:Bronchodilator Agents; D019187:Cadmium Compounds; D049408:Luminescent Agents; D004364:Pharmaceutical Preparations; D017382:Reactive Oxygen Species; D008165:Luminol; D013691:Tellurium; C028337:cadmium telluride; D004837:Epinephrine