The design of intelligent and real-time sensing devices is significant in the medical drug monitoring field, but it is still highly challenging. Here, ratiometric fluorescent detections of ofloxacin (OFL) and its L-isomer levofloxacin (LEV) constructed from tri-doped graphene quantum dots (T-GQDs) are reported, and the detection limits reach as low as 46/67 nM toward OFL/LEV due to the intermolecular electron transfer (intermolecular ET) effect. After adding OFL/LEV, the generation of electrostatic bond provides a channel for the intermolecular ET from the edge of T-GQDs to OFL/LEV, resulting in the fluorescence quenching at 414 nm and the fluorescence promoting at 498 nm. Furthermore, a smartphone can be used for the visual and quantitative detection of OFL and LEV by identifying the RGB values of test paper and drink samples. This work not only reveals the physics mechanism of ratiometric detection, but also develops a convenient smartphone diagnostic for OFL and LEV.

智能实时传感设备的设计在医疗药物监测领域具有重要意义，但仍具有很高的挑战性。在这里，报告了氧氟沙星 (OFL) 及其由三掺杂石墨烯量子点 (T-GQD) 构建的 L-异构体左氧氟沙星 (LEV) 的比率荧光检测，检测限低至 46/67 nM 至 OFL/ LEV 由于分子间电子转移（intermolecular ET）效应。加入OFL/LEV后，静电键的产生为分子间ET从T-GQDs的边缘到OFL/LEV提供了通道，导致414 nm处的荧光猝灭和498 nm处的荧光促进。此外，智能手机可以通过识别试纸和饮料样品的RGB值，对OFL和LEV进行视觉和定量检测。