title: In situ photochemical synthesis of fluorescent carbon dots for optical sensing of hydrogen peroxide and antioxidants.
abstract: A new synthesis approach for obtaining fluorescent carbon dots (CDs) based on UV irradiation of carbohydrates was developed. The photochemical synthesis pathway allows the formation of water soluble CDs of analytical usefulness within one min. CDs obtained by photochemical treatment from the sucrose/NaOH/poly(ethylene glycol) system are monodisperse with an average size of 8 nm as determined by transmission electron microscopy. A dramatic increase in the CDs fluorescence (turn on) is observed when H2O2 is added. The decrease in CDs size occurring by the action of highly oxidant OH radicals gives rise to confinement of emissive energy traps and, in turn, to fluorescence enhancement. Antioxidants such as ascorbic acid and glutathione inhibit the photochemical reaction giving rise to a decrease in fluorescence of the CDs/H2O2 system (turn on-off). The detection limit was 5 µM H2O2 and the repeatability expressed as the relative standard deviation was 3.8% (N=7). The photochemical synthesis of CDs allows building a green, low-cost, safe and fast assay for the detection of H2O2 and antioxidants. An application of the novel fluorescent nanoprobe to H2O2 detection in contact lens cleaning solutions is performed.
authors.affiliation: Departamento de Química Analítica y Alimentaria, Área de Química Analítica, Facultad de Química, Universidad de Vigo, Campus As Lagoas-Marcosende s/n, 36310 Vigo, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Costas-Mora
authors.affiliation: Departamento de Química Analítica y Alimentaria, Área de Química Analítica, Facultad de Química, Universidad de Vigo, Campus As Lagoas-Marcosende s/n, 36310 Vigo, Spain.
authors.forename: Vanesa
authors.initials: V
authors.lastname: Romero
authors.affiliation: Departamento de Química Analítica y Alimentaria, Área de Química Analítica, Facultad de Química, Universidad de Vigo, Campus As Lagoas-Marcosende s/n, 36310 Vigo, Spain.
authors.forename: Isela
authors.initials: I
authors.lastname: Lavilla
authors.affiliation: Departamento de Química Analítica y Alimentaria, Área de Química Analítica, Facultad de Química, Universidad de Vigo, Campus As Lagoas-Marcosende s/n, 36310 Vigo, Spain. Electronic address: bendicho@uvigo.es.
authors.forename: Carlos
authors.initials: C
authors.lastname: Bendicho
keywords: Antioxidants; Carbon dots; Fluorescence; Hydrogen peroxide; Nanoprobe; Photochemical synthesis