A New Rhodamine-based Fluorescent Probe for the Discrimination of Fe3+ from Fe2+

A new rhodamine-based fluorescent probe for the discrimination of Fe3+ from Fe2+ has been designed and investigated. The probe shows an immediate visual color change in response to Fe3+ and Cu2+, while only Fe3+ triggers the fluorescent change of the probe. The existence of large amount of other metal ions shows negligible interference in the detection of Fe3+. The association constant K-ass of 4.64x10(8)M(-2) (R-2 = 0.994) and 5.38x10(8)M(-2) (R-2 = 0.991) of the complex was derived from UV/Vis and fluorescence titration assuming 1:2 stoichiometry of probe-Fe3+ complex, respectively.