Dual-mode detection sensor based on nitrogen-doped carbon dots from pine needles for the determination of Fe3+ and folic acid

In this study, nitrogen-doped carbon dots (N-CDs) from pine needles were obtained by one-step hydrothermal synthesis without any chemical reagents. The fluorescence quenching and absorbance enhancement of N-CDs occurred when Fe3+ and folic acid (FA) were added. Based on this, the dual-mode detection sensor by fluorescence and ultraviolet-visible (UV-Vis) spectrophotometry for the determination of Fe3+ and FA was established. Detected by the dual-mode detection sensor under the optimized condition, the linear range of Fe3+ was 0.1-540 μM and FA was 0.1-165 μM. At the same time, the two inputs "NOR" and "OR" logic gates are constructed successfully according to the dual-mode sensor signals. The proposed dual-mode detection sensor is simple, efficient and stable; it can be applied to determinate Fe3+ and FA in practical samples successfully and the results are satisfactory.