Cobalt-modulated dual emission carbon dots for ratiometric fluorescent vancomycin detection.

This work presents a simple yet selective fluorometric protocol for the quantification of vancomycin, an important antibiotic for treating infections caused by Gram-positive bacteria. A novel ratiometric fluorometric method for the determination of vancomycin is developed based on dual emissive carbon dots (DECDs) with emission at 382 nm and 570 nm in combination with Co ions. Upon addition of Coions, the fluorescence at 382 nm of DECDs is enhanced while emission at 570 nm remains constant. In the presence of vancomycin, it complexes with Co leading to quenching of the 382 nm fluorescence due to strong binding with Co in the Co@DECDs system. The DECDs are fully characterized by TEM and different spectroscopic techniques. The proposed ratiometric method is based on measuring fluorescence ratio (/) against vancomycin concentration and the method exhibits a good linearity range from 0.0 to 120.0 ng mL with a low limit of detection (S/N = 3) of 0.31 ng mL. The method shows good selectivity with minimal interference from potential interfering species. This ratiometric fluorometric approach provides a promising tool for sensitive and specific vancomycin detection in clinical applications.