Abstract In this work, green fluorescent carbon dots with a high relative quantum yield of 74.13% were synthesized by using one-pot hydrothermal hydrolysis of m-phenylenediamine (mPD) and PEG 1500 in H2SO4 solution at 180 °C for 10 h (mPD-CDs). In the presence of mPD-CDs, Fe2+ can form a complex with 1,10-phenanthroline (Fe(II) – phenanthroline) without interference from mPD-CDs, which has an absorption peak centered at 512 nm and its absorbance is sensitive to the concentration of Fe(II) – phenanthroline. Accordingly, a colorimetric method for the detection of Fe2+ was constructed with a limit of detection (LOD) of 2.98 μM. Moreover, the absorption spectrum of the Fe (II)-phenanthroline complex is overlapping with the excitation and emission spectra of mPD-CDs located at 440 and 516 nm, respectively, resulting in an inner filter effect (IFE) which is sensitive to the concentration of Fe(II) – phenanthroline. Correspondingly, a fluorimetric method for the detection of Fe2+ based on the mPD-CDs/phenanthroline system was built with a LOD as low as 0.59 μM. Therefore, colorimetric and fluorimetric dual mode detection of Fe2+ in aqueous solution can be achieved by a carbon dots/phenanthroline system.

中文翻译：

---

基于碳点/菲咯啉系统的比色和荧光双模式检测水溶液中的 Fe2+

摘要 本工作采用间苯二胺 (mPD) 和 PEG 1500 在 H2SO4 溶液中 180 °C 一锅水热水解 10 h 合成了相对量子产率为 74.13% 的绿色荧光碳点 (mPD- CD）。在 mPD-CDs 存在下，Fe2+ 可以与 1,10-菲咯啉（Fe(II) – 菲咯啉）形成复合物而不受 mPD-CDs 的干扰，其吸收峰集中在 512 nm，其吸光度对Fe(II) – 菲咯啉的浓度。因此，构建了检测 Fe2+ 的比色法，检测限 (LOD) 为 2.98 μM。此外，Fe (II)-菲咯啉配合物的吸收光谱与分别位于 440 和 516 nm 的 mPD-CDs 的激发和发射光谱重叠，导致对 Fe(II) – 菲咯啉的浓度敏感的内部过滤效应 (IFE)。相应地，建立了一种基于 mPD-CDs/菲咯啉系统检测 Fe2+ 的荧光方法，其 LOD 低至 0.59 μM。因此，可以通过碳点/菲咯啉系统实现对水溶液中 Fe2+ 的比色和荧光双模式检测。