title: A ratiometric fluorescence sensor for Be2+ based on Beryllon II/layered double hydroxide ultrathin films.
abstract: A ratiometric fluorescence sensor for Be(2+) has been fabricated via alternate assembly of 2-(3,6-disulfo-8-hydroxynaphthylazo)-1,8-dihydroxynaphthalene-3,6-disulfonate (Beryllon II) and MgAl-LDH nanosheets on quartz substrates using the layer-by-layer (LBL) deposition technique. UV-vis absorption and the fluorescence emission spectroscopy indicate a stepwise and regular growth of the Beryllon II/LDH UTFs upon increasing deposition cycle. The film of Beryllon II/LDH possesses a periodic layered structure perpendicular to the substrate revealed by X-ray diffraction and scanning electron microscopy. Atomic force microscopy images show that the film surface is continuous and uniform. The Beryllon II/LDH UTFs display ratiometric fluorescence response for Be(2+) with a linear response range in 1.0×10(-7)-1.9×10(-6) mol L(-1) and a detection limit of 4.2×10(-9) mol L(-1). Furthermore, the ratiometric sensor exhibits good repeatability, high stability (thermal, storage and mechanical) as well as excellent selectivity toward Be(2+). XPS and Raman measurements demonstrate that the specific response of the sensor is attributed to the coordination between Be(2+) and Beryllon II in the UTF. The Beryllon II/LDH UTFs in this work can be potentially used as a chemosensor for the detection of Be(2+) in the environmental and biomedical field.
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China.
authors.forename: Xiaolan
authors.initials: X
authors.lastname: Ji
authors.forename: Wenying
authors.initials: W
authors.lastname: Shi
authors.forename: Shitong
authors.initials: S
authors.lastname: Zhang
authors.forename: Min
authors.initials: M
authors.lastname: Wei
authors.forename: David G
authors.initials: DG
authors.lastname: Evans
authors.forename: Xue
authors.initials: X
authors.lastname: Duan
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D001608:Beryllium / Q000032:analysis*; D002413:Cations, Divalent / Q000032:analysis; D006878:Hydroxides / Q000737:chemistry*; D008958:Models, Molecular; D009281:Naphthalenes / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods*; D014867:Water / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: C431717:2-(3,6-disulfo-8-hydroxynaphthylazo)-1,8-dihydroxynaphthalene-3,6-disulfonate tetrasodium; D001391:Azo Compounds; D002413:Cations, Divalent; D006878:Hydroxides; D009281:Naphthalenes; D014874:Water Pollutants, Chemical; D014867:Water; D001608:Beryllium