Department of Food Science, Shanghai Business School, Shanghai 200235, China.
Molecules. 2022 Mar 25;27(7):2118. doi: 10.3390/molecules27072118.
(1) Background: Carbon quantum dots (CQDs) are a new class of carbon nanomaterials with favorable features, such as tunable luminescence, unique optical properties, water solubility, and lack of cytotoxicity; they are readily applied in biomedicine. (2) Methods: S, N co-doped CQDs were prepared to develop a highly selective and sensitive fluorescence technique for the detection of methotrexate (MTX). For this purpose, citric acid and thiourea were used as C, N, and S sources in a single-step hydrothermal process to prepare the S, N co-doped CQDs, which displayed remarkable fluorescence properties. (3) Results: Two optimal emissions were observed at the excitation/emission wavelengths of 320/425 nm, respectively. The two emissions were significantly quenched in the presence of MTX. Under optimal conditions, MTX was detected in the linear concentration range of 1-300 μmol/L, with the detection limit of 0.33 μmol/L. The sensing mechanism was due to the fact that the effect of the inner filter on MTX and S, N-CQDs causes fluorescence quenching. The contents of MTX in real medicine samples were evaluated with acceptable recoveries of 98-101%. (4) Conclusions: This approach has great potential for detecting MTX in pharmaceutical analysis.
(1) 背景：碳量子点（CQDs）是一类新型的碳纳米材料，具有可调谐发光、独特的光学性质、水溶性和缺乏细胞毒性等优点，在生物医学中得到了广泛的应用。
(2) 方法：制备了 S、N 共掺杂的 CQDs，开发了一种用于检测甲氨蝶呤（MTX）的高选择性和高灵敏度的荧光技术。为此，在一步水热过程中，使用柠檬酸和硫脲作为 C、N 和 S 的来源，制备了具有显著荧光性质的 S、N 共掺杂 CQDs。
(3) 结果：在激发/发射波长分别为 320/425nm 时观察到两个最佳发射峰。在 MTX 的存在下，两个发射峰均显著猝灭。在最佳条件下，MTX 在 1-300μmol/L 的线性浓度范围内得到检测，检测限为 0.33μmol/L。传感机制是由于内滤效应对 MTX 和 S、N-CQDs 的影响导致荧光猝灭。采用该方法对实际药物样品中的 MTX 含量进行了评估，回收率为 98-101%，结果令人满意。
(4) 结论：该方法在药物分析中检测 MTX 具有很大的潜力。
