Highly luminescent carbon quantum dots (CQDs) are developed as fluorescent probes for selective detection of the heavy-ion Fe³⁺, where the CQDs exhibit excellent nontoxicity, functionalizability, sensitivity, and selectivity. Biomass-based CQDs and nitrogen-doped CQDs (N-CQDs) are synthesized for the selective detection of Fe³⁺ by using H₂O₂ as an oxidant and polyetherimide (PEI) as a nitrogen precursor by a green hydrothermal synthesis method. The prepared CQDs and N-CQDs exhibit an elliptical morphology and with an average particle size of 7 and 4 nm, respectively, and emit blue photoluminescence at 445 and 468 nm under excitation at 367 and 343 nm, respectively. The CQDs and N-CQDs exhibit good water solubility because of the abundant hydroxyl and carboxyl/carbonyl groups and graphic/pyrrolic/pyridinic nitrogen on the surfaces, giving rise to a quantum yield of about 24.2% and 30.7%, respectively. Notably, the Matrimony vine-PEI-based CQDs exhibit excellent Fe³⁺ selectivity and sensitivity relative to the Matrimony vine-based CQDs due to complexation of the numerous phenolic hydroxyl groups and nitrogen-containing groups with Fe³⁺, leading to increased fluorescence quenching, which greatly improves the sensitivity of detection. The minimum detection limit was 2.22 µmol L⁻¹ with a complexation constant of 44.7.

高度发光的碳量子点（CQD）被开发为用于选择性检测重离子Fe ^3+的荧光探针，其中CQD表现出优异的无毒性，功能性，敏感性和选择性。合成了基于生物质的CQD和氮掺杂的CQD（N-CQD），用于通过使用H ₂ O ₂选择性检测Fe ³⁺。通过绿色水热合成法将其用作氧化剂，并将聚醚酰亚胺（PEI）作为氮前体。制备的CQD和N-CQD分别显示出椭圆形的形态和平均粒径，分别为7和4 nm，并分别在367和343 nm的激发下在445和468 nm处发出蓝色光致发光。CQD和N-CQD具有良好的水溶性，这是因为表面上有大量的羟基和羧基/羰基以及图形/吡咯/吡啶氮，分别产生了约24.2％和30.7％的量子产率。值得注意的是，由于众多酚羟基和含氮基团与Fe ^3+的络合，基于Matrimony vine-PEI的CQD相对于Matrimony vine的CQD表现出出色的Fe ³⁺选择性和敏感性。导致荧光猝灭的增加，从而大大提高了检测的灵敏度。最小检出限为2.22μmolL ^-1，络合常数为44.7。