A simple rhodamine-based fluorescent probe L1, which exhibits good response to Fe3+ in CH3CN/Tris-HCl buffer (v:v = 9:1, pH 7.00) solution. With the experimental conditions optimized, the probe L1 could be used as a fluorescent and colorimetric probe for Fe3+ with the detection limit as low as 0.29 μM. The binding constant (Ka) of Fe3+ binding to the probe L1 were calculated to be 1.4 × 1010 M-2, respectively from a Benesi-Hildebrand plot. With the addition of Fe3+, the CH3CN/Tris-HCl buffer (v:v = 9:1, pH 7.00) solution of the probe L1 exhibited a obviously color change from transparent to pink with distinctive changes. More importantly, the recognition process of the probe L1 for Fe3+ was chemically reversible on the addition AcO-. Graphical Abstract.
Keywords: Fe3+ ions; Fluorescent probe; Rhodamine 6G hydrazide.