Sensitive ratiometric detection of Al() ions in a 100% aqueous buffered solution using a fluorescent probe based on a peptide receptor

Ratiometric detection of Al( iii ) ions in aqueous buffered solutions is still a significant challenge. Herein, a fluorescent probe 1 based on a dipeptide receptor bearing a pyrene fluorophore was synthesized by solid phase synthesis for the ratiometric detection of Al( iii ) ions in aqueous solutions. The peptidyl bioprobe detected Al( iii ) ions sensitively in a 100% aqueous buffered solution through ratiometric response. Upon the addition of Al( iii ) ions, the excimer emission at 476 nm increased significantly, and the monomer emission at 395 nm decreased considerably. Approximately 3.5 equiv. of Al( iii ) was required for the complete ratiometric response of 1 . Moreover, 1 showed linear responses to nanomolar concentrations (0-500 nM) of Al( iii ) by change in the intensity ratio of the excimer and monomer emissions. The detection limit of 1 for Al( iii ) was 138.1 nM ( R 2 = 0.980) in 100% aqueous solutions. The probe showed highly selective response to Al( iii ) in the presence of 16 metal ions. The fluorescent peptidyl probe was suitable for the ratiometric detection of Al( iii ) ions in ground water, tap water, and urine. The peptidyl bioprobe detected Al( iii ) ions sensitively in a 100% aqueous buffered solution through ratiometric response.