Fluorescent sensing and selective Pb(II) extraction by a dansylamide ion-exchanger

J Am Chem Soc. 2005 May 11;127(18):6514-5. doi: 10.1021/ja050296e.


The (bis)dansylated sulfonamide 1,2-C6H4(NHSO2C10H6-5-N(CH3)2)2 (1) extracted Pb(II) selectively from water into 1,2-dichloroethane via an ion-exchange mechanism and showed fluorescence quenching upon Pb(II) extraction. The distribution ratios for metal extraction (determined by ICP-MS) for Pb(II) were 133-1410 times higher than those for other metal cations [Co(II), Ni(II), Cu(II), Zn(II), and Cd(II)] under identical conditions. Fluorescence quenching was observed upon Pb(II) extraction, which was dependent on Pb(II) concentration. The monodansylated control, C6H5NHSO2C10H6-5-N(CH3)2 (2), showed neither extraction nor quenching, indicating that the fluorescence effects are a direct result of Pb coordination to 1. The observed selectivity for Pb(II) is ascribed to the formation of a low-coordinate binary Pb(II)-Sulfonamido complex in the organic phase.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cations, Divalent
  • Dansyl Compounds / chemistry*
  • Ethylene Dichlorides / chemistry
  • Fluorescent Dyes / chemistry*
  • Lead / chemistry
  • Lead / isolation & purification*
  • Nitrates / chemistry
  • Nitrates / isolation & purification
  • Spectrometry, Fluorescence
  • Water / chemistry


  • Cations, Divalent
  • Dansyl Compounds
  • Ethylene Dichlorides
  • Fluorescent Dyes
  • Nitrates
  • Water
  • 5-dimethylaminonaphthalene-1-sulfonamide
  • Lead
  • ethylene dichloride
  • lead nitrate