Detection of uric acid (UA) is inevitable today, as very less amount of uric acid in human leads to Fanconi Syndrome, Wilson’s disease and cardiovascular disorders. Here, we report an eco-friendly synthesis of a nitrogen-doped carbon dot/Chromium (VI) [N–C dot/Cr (VI)] fluorescent nanoprobe for nanomolar detection of uric acid. N–C dot/Cr (VI) nanoprobe is synthesized using solvent free, fast, easy, green, pyrolysis method, which is characterized using UV–VIS, FTIR, XRD, SEM- EDX and PL technique. Addition of Cr (VI) to fluorescent N–C dot leads to immediate turn OFF in fluorescence with the formation of N–C dot/Cr (VI) nanocomposite. The lowest detection limit of Cr (VI) by N–C dot is 1.42 × 10^–9 M. For the first time, we are reporting uric acid, a reducing agent to reduce Cr (VI) to lower valent Cr (III)/Cr (0). The addition of uric acid turns ON the fluorescence with the elimination of inner filter effect (IFE) thus N–C dot/Cr (VI) nanoprobe functioning as a Turn Off–On fluorescent nanosensor for the detection of UA. The efficiency of the sensor is based on fluorescence resonance energy transfer between N-Carbon dots and chromium (VI). A linear response was noted with every nanomolar addition of uric acid. The lowest detection limit toward sensing of UA is found to be 12.5 × 10^–9 M. Thus, the novelty of this method is nanomolar amount of redox species is enough to form a stable nanocomposite and the N-CDs/Cr (VI) nanocomposite is able to sense nanomolar to millimolar concentration of uric acid within a few seconds. The nanoprobe is found to be stable, simple and cost effective which can be extended for detection of uric acid in vegetables, fruits and also in clinical studies.

今天检测尿酸 (UA) 是不可避免的，因为人体中很少量的尿酸会导致范可尼综合征、威尔逊病和心血管疾病。在这里，我们报告了一种环保型氮掺杂碳点/铬 (VI) [N-C 点/Cr (VI)] 荧光纳米探针的合成，用于纳摩尔浓度检测尿酸。N-C dot/Cr (VI) 纳米探针是使用无溶剂、快速、简单、绿色、热解方法合成的，使用 UV-VIS、FTIR、XRD、SEM-EDX 和 PL 技术进行表征。将 Cr (VI) 添加到荧光 N-C 点会导致荧光立即关闭，形成 N-C 点/Cr (VI) 纳米复合材料。N-C点对Cr(VI)的最低检测限为1.42× ^10-9 M. 我们首次报道了尿酸，一种将 Cr (VI) 还原为较低价 Cr (III)/Cr (0) 的还原剂。添加尿酸打开荧光，消除内部过滤效应 (IFE)，因此 N-C 点 / Cr (VI) 纳米探针用作检测 UA 的关闭-打开荧光纳米传感器。传感器的效率基于 N 碳点和铬 (VI) 之间的荧光共振能量转移。每加入纳摩尔的尿酸，就会注意到线性响应。UA 检测的最低检测限为 12.5 × 10 ^–9 M. 因此，该方法的新颖之处在于纳摩尔量的氧化还原物质足以形成稳定的纳米复合材料，并且 N-CDs/Cr (VI) 纳米复合材料能够在几秒钟内检测纳摩尔至毫摩尔浓度的尿酸。发现纳米探针稳定、简单且具有成本效益，可扩展用于检测蔬菜、水果中的尿酸以及临床研究。