Spectrofluorimetric determination of bupropion using N,S co-doped carbon quantum dots: Mechanistic investigation, response surface optimization, and application to pharmaceutical formulations, spiked plasma and environmental samples

Abstract

In this study, a novel analytical method was developed for the determination of bupropion in pharmaceutical formulations and spiked plasma samples using N, S co-doped carbon quantum dots (N,S CQDs) as a fluorescent probe. The N,S CQDs were thoroughly characterized and its optical properties were investigated. The developed N,S CQDs exhibited blue emission at 435 nm upon excitation at 357 nm. Detailed studies on the sensing mechanism revealed that the fluorescence quenching of the N,S CQDs by bupropion follows a static quenching mechanism, as confirmed by Stern-Volmer analysis and thermodynamic parameters. The quenching parameters were further optimized using a central composite experimental design, and the method was validated according to ICH guidelines. The method displayed excellent linearity in the range of 0.05–1.5 μg/mL, with a limit of detection of 0.016 μg/mL. The developed method was successfully applied for the analysis of bupropion in pharmaceutical formulations and spiked human plasma samples, with satisfactory recoveries. Moreover, statistical analysis revealed no significant differences between the results obtained using the proposed method and a reference HPLC method, indicating the reliability of the developed approach. Greenness and blueness of the method was evaluated using the AGREE and BAGI tools respectively, demonstrating the environmentally friendly and analytical practicality of the proposed technique.