School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
Key Laboratory for Thin Film and Microfabrication Technology (Ministry of Education), Shanghai Jiao Tong University, Shanghai, 200240, China.
Mikrochim Acta. 2019 Apr 10;186(5):278. doi: 10.1007/s00604-019-3400-2.
Highly fluorescent carbon quantum dots co-doped with selenium and nitrogen (SeN-CQDs) were fabricated via a one-pot hydrothermal route using selenomethionine as the sole precursor. The SeN-CQDs aggregates have sizes between 30 and 45 nm and display blue fluorescence with a quantum yield of 8% at excitation/emission wavelengths of 350/445 nm. The fluorescence is pH dependent and decreases under acidic conditions. The doping of the CQDs with selenium and nitrogen was proven by X-ray photoelectron spectroscopy (XPS). Fluorescence is selectively quenched by perfluorooctanoic acid (PFOA), and this is accompanied by a decreased fluorescence lifetime. Quenching is not due to aggregation in view of the unaltered sizes of nanoparticles as revealed by TEM and DLS analyses. UV-vis absorption titration suggested the formation of an excited state complex between SeN-CQDs and PFOA, and quenching originates from the internal electron transfer in the excited state complex. The method was used to detect PFOA quantitatively in the linear range of 10-70 μM with a 1.8 μM detection limit. The nanoprobe has a high selectivity for PFOA over potentially interfering molecules. The practicability of the method was ascertained by accurate detection of PFOA in real samples by the standard addition method. The method may be further improved by tuning the interaction between PFOA and SeN-CQDs through optimizing the doping and the surface composition of the SeN-CQDs. Graphical abstract Schematic presentation of a fluorometric method for perfluorooctanoic acid detection by using a selenium and nitrogen co-doped carbon quantum dots as the fluorescent probe.
采用一锅水热法，以硒代蛋氨酸为唯一前驱体制备了硒氮共掺杂的荧光碳量子点（SeN-CQDs）。SeN-CQDs 聚集体的尺寸在 30 至 45nm 之间，在 350/445nm 的激发/发射波长下显示出蓝色荧光，量子产率为 8%。荧光对 pH 值敏感，在酸性条件下会减弱。X 射线光电子能谱（XPS）证明了 CQDs 中硒和氮的掺杂。全氟辛酸（PFOA）能选择性猝灭荧光，同时荧光寿命也会降低。考虑到 TEM 和 DLS 分析表明纳米颗粒的尺寸没有变化，因此猝灭不是由于聚集引起的。紫外可见吸收滴定表明，SeN-CQDs 和 PFOA 之间形成了激发态复合物，猝灭源于激发态复合物中的内部电子转移。该方法用于在 10-70μM 的线性范围内定量检测 PFOA，检测限为 1.8μM。该纳米探针对 PFOA 具有很高的选择性，相对于潜在干扰分子具有较高的选择性。通过标准加入法在实际样品中准确检测 PFOA，确定了该方法的实用性。通过优化 SeN-CQDs 的掺杂和表面组成，可以进一步改善该方法，从而改善 PFOA 和 SeN-CQDs 之间的相互作用。
