Abstract A hydrothermal method was used for the preparation four kinds of nitrogen-doped carbon quantum dots (NCQDs) by using citric acid as the carbon source and ethylenediamine (EDA), urea (U), melamine (MA) and ammonia solution (AS) as the nitrogen source, respectively. The NCQDs were characterized by TEM, FT-IR and XPS, and the optical properties were studied by UV–vis and fluorescence spectra. It is found that the NCQDs(AS) from ammonia solution (AS) as nitrogen source are uniform size spherical nanoparticles and have prominent optical properties. Influencing factors including solution acidity, interfering substances, Ag+ ions concentration and glucose concentration on the detection of glucose are taken into account. In the presence of Ag+ ions, the fluorescence of NCQDs(AS) in aqueous solution was severely quenched due to the surface energy transfer from NCQDs(AS) to Ag+ ions. In weakly alkaline condition, the detected glucose is oxidized to gluconic acid and Ag+ ions are reduced to Ag in aqueous solution at 60 °C. Thereby, the abscission of Ag+ ions from the surface of NCQDs(AS) results in the fluorescence recovery of NCQDs(AS). The glucose can be analyzed quantitatively by NCQDs(AS) in the presence of Ag+ ions with a wide linear region (0.1 μM–1000 μM) and low limit of detection (LOD) (0.375 μM). Also, the selectivity and anti-interference ability experiment of the NCQDs(AS) in the presence of Ag+ ions for glucose detection were discussed. In addition, cytotoxicity and cell imaging experiments of NCQDs(AS) were researched. Overall, the prepared NCQDs(AS) are expected to be widely used in different biological research fields.

中文翻译：

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氮掺杂碳量子点（NCQDs）的制备及其在葡萄糖非酶法检测中的应用

摘要 以柠檬酸为碳源，以乙二胺（EDA）、尿素（U）、三聚氰胺（MA）和氨溶液（AS）为原料，采用水热法制备了四种氮掺杂碳量子点（NCQDs）。分别作为氮源。NCQDs 通过 TEM、FT-IR 和 XPS 进行表征，并通过 UV-vis 和荧光光谱研究其光学性质。发现以氨溶液（AS）为氮源的NCQDs（AS）是大小均匀的球形纳米粒子，具有突出的光学特性。考虑了溶液酸度、干扰物质、Ag+离子浓度和葡萄糖浓度等对葡萄糖检测的影响因素。在 Ag+ 离子的存在下，由于表面能从 NCQDs(AS) 转移到 Ag+ 离子，水溶液中 NCQDs(AS) 的荧光被严重淬灭。在弱碱性条件下，检测到的葡萄糖在 60 °C 的水溶液中被氧化为葡萄糖酸，Ag+ 离子在水溶液中被还原为 Ag。因此，Ag+ 离子从 NCQDs(AS) 表面的脱离导致 NCQDs(AS) 的荧光恢复。在 Ag+ 离子存在的情况下，可以通过 NCQDs(AS) 对葡萄糖进行定量分析，具有宽线性区域 (0.1 μM–1000 μM) 和检测下限 (LOD) (0.375 μM)。此外，还讨论了NCQDs(AS)在Ag+离子存在下用于葡萄糖检测的选择性和抗干扰能力实验。此外，还研究了NCQDs(AS)的细胞毒性和细胞成像实验。全面的，