A ratiometric fluorescent sensor for zinc ions based on covalently immobilized derivative of benzoxazole

Spectrochim Acta A Mol Biomol Spectrosc. 2009 Aug 15;73(4):687-93. doi: 10.1016/j.saa.2009.03.023. Epub 2009 Apr 1.

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.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Benzoxazoles / chemical synthesis
  • Benzoxazoles / chemistry*
  • Cations / analysis*
  • Environmental Monitoring / economics
  • Environmental Monitoring / instrumentation*
  • Environmental Monitoring / methods
  • Hydrogen-Ion Concentration
  • Reproducibility of Results
  • Rivers / chemistry
  • Sensitivity and Specificity
  • Spectrometry, Fluorescence / methods*
  • Time Factors
  • Water / analysis*
  • Water Pollutants, Chemical / analysis
  • Zinc / analysis*

Substances

  • Benzoxazoles
  • Cations
  • Water Pollutants, Chemical
  • Water
  • Zinc