title: A ratiometric fluorescent sensor for zinc ions based on covalently immobilized derivative of benzoxazole.
abstract: In the present paper, we describe the fabrication and analytical characteristics of fluorescence-based zinc ion-sensing glass slides. To construct the sensor, a benzoxazole derivative 4-benzoxazol-2'-yl-3-hydroxyphenyl allyl ether (1) with a terminal double bond was synthesized and copolymerized with 2-hydroxyethyl methacrylate (HEMA) on the activated surface of glass slides by UV irradiation. In the absence of Zn(2+) at pH 7.24, the resulting optical sensor emitted fluorescence at 450 nm via excited-state intramolecular proton transfer (ESIPT). Upon binding with Zn(2+), the ESIPT process was inhibited resulting in a 46 nm blue-shift of fluorescence emission. Thus, the proposed sensor can behave as a ratiometric fluorescent sensor for the selective detection of Zn(2+). In addition, the sensor shows nice selectivity, good reproducibility and fast response time. Cd(2+) did not interfere with Zn(2+) sensing. The sensing membrane demonstrates a good stability with a lifetime of at least 3 months. The linear response range covers a concentration range of Zn(2+) from 8.0x10(-5) to 4.0x10(-3) mol/L and the detection limit is 4.0x10(-5) mol/L. The determination of Zn(2+) in both tap and river water samples shows satisfactory results.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
authors.forename: Qiu-Juan
authors.initials: QJ
authors.lastname: Ma
authors.forename: Xiao-Bing
authors.initials: XB
authors.lastname: Zhang
authors.forename: Xu-Hua
authors.initials: XH
authors.lastname: Zhao
authors.forename: Yi-Jun
authors.initials: YJ
authors.lastname: Gong
authors.forename: Jian
authors.initials: J
authors.lastname: Tang
authors.forename: Guo-Li
authors.initials: GL
authors.lastname: Shen
authors.forename: Ru-Qin
authors.initials: RQ
authors.lastname: Yu
mesh_terms: D001583:Benzoxazoles / Q000138:chemical synthesis / Q000737:chemistry*; D002412:Cations / Q000032:analysis*; D004784:Environmental Monitoring / Q000191:economics / Q000295:instrumentation* / Q000379:methods; D006863:Hydrogen-Ion Concentration; D015203:Reproducibility of Results; D045483:Rivers / Q000737:chemistry; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013997:Time Factors; D014867:Water / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis; D015032:Zinc / Q000032:analysis*
chemical_list: D001583:Benzoxazoles; D002412:Cations; D014874:Water Pollutants, Chemical; D014867:Water; D015032:Zinc