N-doped carbon dots for the determination of Al 3+ and Fe 3+ using aggregation-induced emission

New portable hydrogel sensors for Al 3+ and Fe 3+ detection were designed based on the aggregation-induced emission (AIE) and color change of N-doped carbon dots (N-CDs). N-CDs with yellow fluorescence were prepared by a one-pot hydrothermal method from 2,5-dihydroxyterephthalic acid and acrylamide. The fluorescence of N-CDs was enhanced by Al 3+ about 20 times and quenched by Fe 3+ . It was interesting that although Fe 3+ showed obvious quenching on the fluorescence of N-CDs it did not cause a noticeable change in the fluorescence of N-CDs + Al 3+ . The colorless solution of N-CDs appeared blue in the presence of Fe 3+ without the influence of Al 3+ . Therefore, the turn-on fluorometry and colorimetry systems based on N-CDs were constructed for the simultaneous detection of Al 3+ and Fe 3+ . Furthermore, the portable sensing of Al 3+ and Fe 3+ was realized with the assistance of hydrogel, filter paper, cellulose acetate, and cellulose nitrate film. The proposed approach was successfully applied to the detection of Al 3+ and Fe 3+ in food samples and cell imaging. Graphical Abstract