A fluorescence switch-off nanosensor for sensitive determination of the antiandrogen drug flutamide in pharmaceutical and environmental samples. Analytical method greenness, blueness, and whiteness assessment

Abstract

A fast, practical, and non-hazardous switch-off fluorescent nanosensor for the non-fluorescent antiandrogen drug flutamide (FLU) was developed from nitrogen/sulfur co-doping of carbon quantum dots (N,S-CQDs). For the first time, the highly fluorescent N,S-CQDs were generated via one-pot microwave-assisted synthesis in only 3 min using facilely available precursors (sweet yellow pepper and thiourea). The sensor is characterized by a narrow particle size distribution, high doping efficiency (N, 42.05 % and S, 8.28 %), reproducibility, and high emission at 410 nm after excitation at 330 nm. FLU efficiently and quantitatively turned off the fluorescence of the prepared N,S-CQDs via a synergistic combination of static quenching and inner filter effect. The furnished nanosensor showed good linearity (r = 0.9999) for FLU analysis within concentrations ranged from 1.0 to 30.0 µg mL−1 with a detection limit of 0.293 µg mL−1 and quantitation limit of 0.886 µg mL−1. The selectivity of the probe was confirmed in the presence of co-administered drugs, possible co-existing materials, and various metal ions. The N,S-CQDs interestingly showed acceptable cytocompatibility and low toxicity, as revealed by the MTT assay. This feature bestows the N,S-CQDs a practicability as an environmental sensor. Thus, the proposed approach was implemented for FLU analysis in pharmaceutical tablets, tap water, and river water with good percentage recoveries (99.59 ± 1.28%, 99.49 ± 1.75%, and 101.21 ± 1.67%, respectively) and without interferences. Furthermore, the approach was positively assessed with respect to greenness, blueness, and whiteness. The high values of the analytical greenness score AGREE (0.78), the chiefly green ComplexGAPI pictogram, the Blue Applicability Grade Index BAGI (72.5), and the RGB12 (93.6) show the high greenness, blueness, and whiteness features of the method that confirm its minor environmental impact, excellent applicability, and sustainability, respectively.