A novel dansyl-based fluorescent probe for Fe3+

A novel structurally simple dansyl-based fluorescent probe, 5-(dimethylamino)-N,N-bis(2-hydroxyethyl)naphthalene-1-sulfonamide, was synthesized from dansyl chloride and diethanolamine under very mild reaction conditions. The structure of the probe was fully characterized by nuclear magnetic resonance spectra, infrared spectroscopy, high resolution mass spectra, and elemental analysis. The probe was highly selective and sensitive to Fe3+ in H2O/CH3CN (1/99, v/v). The linear concentration range for Fe3+ was 0-100 mu M with a fluorescent detection limit of 3.45 mu M. The probe responded to Fe3+ within 5 min and possessed excellent anti-interference ability. Moreover, the probe reversibly chelated Fe3+ at a 1:1 stoichiometry with a binding constant of 7.94 x 10(4) M-1. The sensing mechanism was supported by mass spectroscopic technique.