基于氮掺杂碳点的荧光增强简便、快速而准确地检测环丙沙星

以苹果酸为碳源,磷酸铵提供氮源,采用固态热解法一步合成一种水溶性的、氮掺杂的蓝色荧光碳点(N-CDs)。 所得到的碳点荧光量子产率高达20.7%,形貌近似球形,平均粒径约为3.3 nm。 基于环丙沙星(CIP)对碳点的荧光增强作用,建立了一种CIP的定量检测方法。 最佳实验参数为:碳点浓度为7.5 μg/mL,pH值为5.9,孵化时间为5 min。 在此实验条件下,碳点的荧光强度增加值(ΔF)和CIP的浓度在0.39~40.00 μmol/L范围内呈良好的线性关系,方法的检出限为0.12 μmol/L,相对标准偏差(n=5)为4.2%。 干扰实验结果指出,除了铜离子具有明显的影响外,其它共存物质的干扰可以忽略不计,而铜离子的干扰可通过加入草酸铵来掩蔽。 最后利用所构建的荧光传感器对实际样品中CIP进行检测,回收率在93%~107%之间。 本研究为CIP定量分析提供了一种简单、快速、灵敏度高、选择性好而有效的测定方法。

Simple,Fast and Accurate Detection of Ciprofloxacin Based on Fluorescence Enhancement of Nitrogen-Doped Carbon Dots

Nitrogen doped fluorescence carbon dots (N-CDs) were successfully synthesized by a facile one step solid phase pyrolysis treatment using malic acid as the carbon source and ammonium phosphate as the nitrogen source. The fluorescence quantum yield of the obtained N-CDs reaches 20.7% and the N-CDs have approximately spherical morphology with an average diameter of 3.3 nm. The as prepared N-CDs were used as the fluorescent probe to detect ciprofloxacin (CIP) based on the enhancement of N-CDs fluorescence upon adding CIP. The optimal experimental mass conditions are 7.5 μg/mL of N-CDs, pH=5.91, and 5 min of incubation time for the detection of CIP. The enhancement of N-CDs fluorescence exhibits a good linear relationship with the concentration of CIP ranged from 0.39 μmol/L to 40.0 μmol/L under the optimal conditions. The linear regression equation is ΔF=1.61×10⁷CIP]-3.28 with a correlation coefficient R²=0.994. The detection limit and relative standard deviation (n=5) are estimated to be 0.12 mol/L and 4.2%, respectively. The interference experiments indicate that potential coexistence substances (except copper ions) have ignorable effects on the detection of CIP, and the interference of copper ions could be masked with 4% ammonium oxalate solution. Finally, the proposed sensor was successfully applied to analyze real samples with satisfactory results.