Jute Mallow Leaves Biomass as a Green Source for the Microwave-Assisted Synthesis of N,S-Carbon Quantum Dots: Application to the Sensitive Sensing of the Anticancer Drug Afatinib in Environmental Water Samples

This research presents a novel and efficient microwave-assisted method for synthesizing nitrogen- and sulfur-doped carbon quantum dots (N,S-CQDs) using Corchorus olitorius leaves (Jute mallow) as a sustainable green carbon source and thiourea as a nitrogen and sulfur source. The method achieves remarkable efficiency, enabling the synthesis of N,S-CQDs in just 50 s. Diverse characterization approaches validated the distinctive optical and morphological characteristics of the N,S-CQDs. The quantum yield of the N,S-CQDs was determined to be as high as 22%, indicating their high efficiency as fluorescent nanoprobes. The N,S-CQDs have switch-off fluorescence characteristics suitable for determining the anticancer afatinib in various environmental water samples. The method demonstrated outstanding linearity across a range of 1.0–12.0 μg/mL (R² > 0.999) and a limit of detection as low as 0.13 μg/mL. The analysis of afatinib in numerous water samples with high percentage of recoveries revealed the efficacy of N,S-CQDs as a sensitive detection platform. A holistic evaluation of the greenness, practicality, and efficiency of the method was performed using diverse metrics, validating its exceptional eco-friendliness and broad application. This innovative research facilitates the development of environmentally sustainable nanoprobes with much relevance in ecological monitoring.