Dual-emission carbon dots for ratiometric detection of Fe3+ ions and acid phosphatase.

We have developed a simple and convenient route to prepare fluorescent carbon dots with dual emission peaks respectively at 470 and 570 nm. The prepared dual-emission carbon dots can be used for ratiometric detection of Fe3+ ions in the range from 0 to 50 μmol·L-1 with 0.8 μmol·L-1 detection limit based on the fluorescence quenching at 570 nm. The quenched fluorescence induced by Fe3+ ions could be recovered by pyrophosphate. We further used the carbon dots-Fe3+ ions-pyrophosphate mixed system for ratiometric detection of acid phosphatase in the range from 0.08 to 6.75 μg·mL-1 with 0.01 μg·mL-1 detection limit. Image 1 • The carbon dots were directly prepared by carbonizing gallic acid and o-phenylenediamine in aqueous solutions. • The carbon dots exhibited dual emission peaks at 470 nm and 570 nm with excitation of 360 nm. • An obvious fluorescence quenching around 570 nm was observed with the addition of Fe3+ in acidic environments. • The GN-CDs can be used as a ratiometric probe for detection of Fe3+ ions and acid phosphatase. [ABSTRACT FROM AUTHOR]