Bioinspired carbon dot-Ag nanocomposite derived from basil leaves for sensitive electrocatalytic detection of ciprofloxacin

초록

Rapid identification of antibiotic residues is crucial for environmental surveillance and ecological balance. In this study, carbon dots (CDs) were synthesized using a green approach with Thai basil leaves and utilized for the synthesis of carbon dot-silver nanoparticles (CD-AgNPs) nanocomposite for electrochemical sensing of ciprofloxacin (CPX) in environmental samples. Morphological characterization revealed predominantly spherical CDs and CD-AgNPs, with an average diameter of 5 nm and 20.24 +/- 2.5 nm, respectively. Modification of the glassy carbon electrode (GCE) with CD-AgNPs increased the effective surface area (Ae) from 0.040 to 0.087 cm2, and the charge transfer resistance (Rp) decreased significantly from 2842 to 851 k Omega. Surface coverage (Gamma*) of CPX was 6.593 & times; 10- 11 mol cm- 2. Electrochemical studies revealed a two-electron oxidation mechanism with a rate constant (k0) of 0.1157 s- 1 and a standard peak potential (E0) of 1.077 V, leading to CPX radical generation. The sensor achieved an impressive limit of detection (LOD) (0.1124 & micro;M), limit of quantification (LOQ) (0.3746 & micro;M), and sensitivity (0.7977 & micro;A & micro;M- 1 cm- 2) within the 0.25-40 & micro;M range. Selectivity tests indicated minimal interference from other antibiotics, and signal degradation was limited to 11.4% after 10 consecutive measurements. Application to tap and river water demonstrated recovery rates of nearly 100%, aligning with highperformance liquid chromatography (HPLC) analysis. Overall, Thai basil-derived CD-AgNPs demonstrate highperformance electrochemical sensors for efficient CPX detection.

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