title: Quantum dots as a possible oxygen sensor.
abstract: Results of studies on optical properties of low toxicity quantum dots (QDs) obtained from copper doped zinc sulfate are discussed in the paper. The effect of copper admixture concentration and solution pH on the fluorescence emission intensity of QDs was investigated. Quenching of QDs fluorescence by oxygen was reported and removal of the oxygen from the environment by two methods was described. In the chemical method oxygen was eliminated by adding sodium sulfite, in the other method oxygen was removed from the solution using nitrogen gas. For elimination of oxygen by purging the solution with nitrogen the increase of fluorescence intensity with decreasing oxygen concentration obeyed Stern-Volmer equation indicating quenching. For the chemical method Stern-Volmer equation was not fulfilled. The fluorescence decays lifetimes were determined and the increase of mean lifetimes at the absence of oxygen support hypothesis that QDs fluorescence is quenched by oxygen.
authors.affiliation: Institute of General Food Chemistry, Lodz University of Technology, Stefanowskiego 4/10, 90-924 Łódź, Poland.
authors.forename: Paulina
authors.initials: P
authors.lastname: Ziółczyk
authors.affiliation: Institute of General Food Chemistry, Lodz University of Technology, Stefanowskiego 4/10, 90-924 Łódź, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Kur-Kowalska
authors.affiliation: Institute of General Food Chemistry, Lodz University of Technology, Stefanowskiego 4/10, 90-924 Łódź, Poland.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Przybyt
authors.affiliation: Institute of General Food Chemistry, Lodz University of Technology, Stefanowskiego 4/10, 90-924 Łódź, Poland. Electronic address: ewa.miller@p.lodz.pl.
authors.forename: Ewa
authors.initials: E
authors.lastname: Miller
mesh_terms: D003300:Copper / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D010100:Oxygen / Q000032:analysis*; D045663:Quantum Dots / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods; D013440:Sulfides / Q000737:chemistry*; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D005456:Fluorescent Dyes; D013440:Sulfides; D017967:Zinc Compounds; D003300:Copper; C031238:zinc sulfide; D010100:Oxygen
keywords: Fluorescence; Oxygen sensor; Quantum dots; Quenching