Biomass Carbon Dots as Fluorescent Probes for Fast and Highly Selective Detection of Fe^{3 +} in Water Media

In this study, a novel fluorescent probe for the rapid and highly selective detection of Fe^{3 +} based on biomass carbon dots (b-CDs) was developed. The b-CDs were obtained via one-step hydrothermal synthesis by utilizing laurel fallen leaves. And the as-synthesized b-CDs were applied for sensing Fe³⁺ based on fluorescence (FL) quenching effect both in water and phosphate buffer solution (PBS) with a wide linear range from 1 µM to 300 µM, the detection limits (LODs) respectively to be 0.34 µM in water and 0.48 µM in PBS solution. The FL intensity of b-CDs was quenched fleetly within 1 min after adding Fe³⁺. The sensing mechanism of the b-CDs + Fe³⁺ system can be attributed to the internal filtration effect (IFE) mechanism and the electron transfer (ET) between b-CDs and Fe³⁺ in water, and only the IFE mechanism in PBS solution based on multiple experimental evidences. Moreover, the as-proposed probe was successfully adopted for monitoring Fe³⁺ in lake water and tap water samples. This research shows some merits of economic, simplicity, green, high selectivity, and quick response for Fe³⁺ determination, and provides an approach for the water quality monitoring of Fe³⁺ and the effective utilization of waste biological materials.