A novel turn-off green carbon dot-based fluorescent probe for selective determination of nitrazepam in its pharmaceutical dosage form and milk samples†

In this study, a new, rapid, simple, and cost-effective fluorescent probe based on carbon dots (CDs) has been developed for the selective determination of nitrazepam (NZP). The CDs were synthesized with high production yield (71.43%) through one step carbonization of dried banana peels. The fluorescence intensity of the CDs is quenched by increasing the NZP concentration as a result of the inner-filter effect and dynamic quenching mechanism. This fluorescent sensor effectively quantified NZP in the linear range of 0.30–26 μg mL⁻¹, with a limit of detection of 0.10 μg mL⁻¹. The performance of the sensor was validated according to ICH guidelines and exhibited high precision and accuracy. The proposed method was also successfully extended for determining NZP in tablet dosage form and milk samples.