School of Chemistry and Chemical Engineering, Anhui University of Technology, Ma'anshan, 243032, China.
Institute of Pharmaceutical Analysis, College of Pharmacy, Jinan University, Guangzhou, 510632, China.
Anal Chim Acta. 2022 Jul 11;1216:339991. doi: 10.1016/j.aca.2022.339991. Epub 2022 May 28.
In this work, copper-doped zinc sulfide quantum dots (ZnS:Cu QDs) were developed as ratiometric fluorescent probes to detect tetracycline (TC) in milk. With the increasing of TC concentration, the fluorescence at 578 nm of ZnS:Cu QDs was quenched, while a new fluorescence at 520 nm was significantly enhanced due to the formation of a green-emitting complex of Zn and TC on the surface of probes. The fluorescence intensity ratio (I/I) have a good linear relationship (R = 0.98) with the concentration of TC in the range of 0.2-2.0 μM. The detection limit was calculated to 149 nM, which is lower than the allowable level of TC (about 180 μM) in milk set by the US Food and Drug Administration (FDA). Finally, the fluorescent test papers have been also prepared using ZnS:Cu QDs as ink by painting on a piece of filter paper. With the addition of TC, the orange test paper produced green spots that became more and more obvious with a dose-discerning ability as low as 2 μM. This work demonstrated a great potential of ratiometric fluorescent probe for the easy and visual detection of TC in complicated real samples.
在这项工作中，合成了铜掺杂硫化锌量子点（ZnS:Cu QDs）作为比率荧光探针，用于检测牛奶中的四环素（TC）。随着 TC 浓度的增加，ZnS:Cu QDs 在 578nm 处的荧光被猝灭，而由于探针表面形成了 Zn 和 TC 的绿色发射配合物，在 520nm 处产生了新的显著增强的荧光。荧光强度比（I/I）与 0.2-2.0μM 范围内 TC 的浓度呈良好的线性关系（R=0.98）。检测限计算为 149nM，低于美国食品和药物管理局（FDA）规定的牛奶中 TC 的允许水平（约 180μM）。最后，还使用 ZnS:Cu QDs 作为墨水通过在滤纸上绘画来制备荧光试纸。加入 TC 后，橙色试纸产生绿色斑点，随着剂量的降低，其识别能力越来越强，低至 2μM。这项工作展示了比率荧光探针在复杂实际样品中用于 TC 的简便可视化检测的巨大潜力。
