Adenosine capped CaF2:Eu3+ nanocrystals and their applications in permanganate detection

Abstract The authors report a luminescence method based on energy transfer for the determination of permanganate ion in an aqueous medium. This is achieved using adenosine-capped CaF2:Eu3+ nanocrystals. Here, adenosine acts as a surfactant and a sensitizer for the Eu3+ ion in the CaF2 host matrix. The close proximity of the permanganate ion to the sensitizing adenosine molecules can alter the efficiency of energy transfer between the sensitizer and Eu3+ ions, which leads to quenching of Eu3+ emission. The adenosine-capped CaF2:Eu3+ luminescent probe shows strong red emission originating from Eu3+, with two predominant peaks at 592 and 615 nm, when excited at 321 nm. The gradual addition of permanganate ions to the nanocrystals aqueous dispersion significantly decreased the intensity of Eu3+ luminescence signal. The linear range of the determination was from 10 nM to 6 μM for the MnO4− ion (R2 = 0.99). The calculated detection limit was 10.46 nM.