title: Enhancing reactive species generation upon photo-activation of CdTe quantum dots for the chemiluminometric determination of unreacted reagent in UV/S2O8(2-) drug degradation process.
abstract: A new chemiluminescence (CL) flow method for persulfate determination was developed based on luminol oxidation by in-line generated radicals. Reactive oxygen species (ROS) generated by CdTe quantum dots (QDs) under a low energetic radiation (visible light emitted by LEDs) promoted the decomposition of persulfate ion (S2O8(2-)) into sulfate radical (SO4(∙-)), leading to subsequent radical chain reactions that yield the emission of light. Due to the inherent radical short lifetimes and the transient behavior of CL phenomena an automated multi-pumping flow system (MPFS) was proposed to improve sample manipulation and reaction zone implementation ensuring reproducible analysis time and high sampling rate. The developed approach allowed up to 60 determinations per hour and determine S2O8(2-) concentrations between 0.1 and 1 mmol with good linearity (R=0.9999). The method has shown good repeatability with relative standard deviations below 2.5% (n=3) for different persulfate concentrations (0.1 and 0.625 mmol L(-1)). Limits of detection (3σ) and quantification (10σ) were 2.7 and 9.1 µmol L(-1), respectively. The MPFS system was applied to persulfate determination in bench scale UV/S2O8(2-) drug degradation processes of model samples showing good versatility and providing real time information on the persulfate consumption in photo-chemical degradation methodologies.
authors: Instituto de Química, Universidade Federal da Bahia, Rua Barão de Geremoabo Ferreira, 147, 40170-150 Salvador, Bahia, Brazil.
authors: Rodolfo M M
authors: RM
authors: Santana
authors: Universidade Federal de Juiz de Fora, Faculdade de Farmácia e Bioquímica, Rua José Lourenço Kelmer, s/n, 36036-900 Juiz de Fora, Minas Gerais, Brazil.
authors: Thaís D
authors: TD
authors: Oliveira
authors: REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
authors: S Sofia M
authors: SS
authors: Rodrigues
authors: REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal.
authors: Christian
authors: C
authors: Frigerio
authors: REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
authors: João L M
authors: JL
authors: Santos
authors: Departamento de Ciências Exatas e da Terra, Universidade do Estado da Bahia, R. Silveira Martins, 2555, Cabula, 41195-001 Salvador, Bahia, Brazil. Electronic address: mkorn@uneb.br.
authors: Mauro
authors: M
authors: Korn
mesh_terms: D015097:3-Mercaptopropionic Acid / Q000737:chemistry / Q000528:radiation effects*; D019187:Cadmium Compounds / Q000737:chemistry / Q000528:radiation effects*; D008027:Light; D008165:Luminol / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry; D010084:Oxidation-Reduction; D017680:Potassium Compounds / Q000737:chemistry / Q000528:radiation effects*; D045663:Quantum Dots / Q000737:chemistry / Q000528:radiation effects*; D017382:Reactive Oxygen Species / Q000737:chemistry*; D013431:Sulfates / Q000737:chemistry / Q000528:radiation effects*; D013691:Tellurium / Q000737:chemistry / Q000528:radiation effects*
chemical_list: D019187:Cadmium Compounds; D017680:Potassium Compounds; D017382:Reactive Oxygen Species; D013431:Sulfates; D008165:Luminol; C009007:potassium persulfate; D015097:3-Mercaptopropionic Acid; D013691:Tellurium; C028337:cadmium telluride
keywords: CdTe; Drug photo-chemical degradations; Multi-pumping flow system; Persulfate determination; Quantum dots