"Turn-on" fluorescent probes based on Rhodamine B/amino acid derivatives for detection of Fe3+ in water

Five kinds of Fe3+ fluorescent probes (RhB-Gly, RhB-Ala, RhB-Try, RhB-Cys, and RhB-His) were synthesized and characterized by NMR and mass spectrometry, based on the "OFF-ON" mechanism of Rhodamine B derivatives. The RhB-His based probe showed remarkable sensing performance toward the detection for Fe3+ and showed high selectivity for Fe3+ in the presence of other metal ions (such as Fe2+, Hg2+, Zn2+, Ba2+, Al3+, Co2+, Cd2+, K+, Na+, Mn2+, Pd2+, Pb2+, Ca2+, Ni2+, Cu2+, and Ag+), in PBS buffer solution (containing 2% of EtOH, pH 7.4, 1.0 mmol/L). The enhancement of the fluorescence was linearly proportional with the concentration Fe3+ (from 0 to 20 mu mol/L), while the detection limit reached 0.88 mu mol/ L with a response time of 15 s. The RhB-His probe was successfully applied to investigate real samples and living cell imaging. (C) 2020 Elsevier B.V. All rights reserved.