Innovative Microwave‐Assisted Fabrication of N,S‐Doped Carbon Quantum Dots as Fluorescent Nanosensors for the Sensitive Monitoring of Lapatinib in Plasma and Water Samples: A Holistic Evaluation of Greenness, Efficiency, and Novelty

An environmentally benign microwave-assisted method was developed to synthesize nitrogen and sulfur co-doped carbon quantum dots (N,S-CQDs) from Cichorium intybus leaves, enabling their use as efficient fluorescent nanosensors. The method is incredibly quick, enabling the acquisition of N,S-CQDs in under 50 s. Their unique optical and structural characteristics were confirmed by thorough characterization using HR-TEM, EDX, zeta potential, FT-IR, UV-Vis, and fluorescence spectroscopy. The N,S-CQDs exhibited a quantum yield of 24%, highlighting their strong potential as fluorescent nanoprobes. Notably, they displayed switch-off fluorescence behavior suitable for the determination of the anticancer drug lapatinib in spiked human plasma and environmental water samples. The method demonstrated excellent linearity across 0.2-8.0 μg/mL (r > 0.999) with a detection limit of 0.05 μg/mL. High recovery values in plasma and water matrices further validated the sensitivity and accuracy of the approach. Moreover, sustainability and performance were systematically evaluated using the Analytical Green Star Area (AGSA) and the Multi-color Assessment platform for White Analytical Chemistry (MA-tool), confirming the technique's environmental friendliness, broad applicability, analytical robustness, and novelty. This pioneering work paves the way for the development of green nanoprobes with significant relevance in biological and environmental monitoring.