Selective determination of vancomycin in human serum using graphene quantum dots modified with Dihydroxyl functional groups

In this study, graphene quantum dots (GQDs) with a high density of carboxyl groups were synthesized via a thermal dissolution method. The surface carboxyl groups of the GQDs were then conjugated with the amino groups of dopamine (DA) through an amidation reaction, yielding a novel fluorescent prob.(GQDs@DA), which features catechol groups. Leveraging the distinctive catechol moiety of vancomycin (VAN) as a functional handle, we employed GQDs@DA and a sol-gel process to construct molecularly imprinted polymers (MIPs@GQDs@DA) on a SiO₂ matrix. This resulted in the formation of highly selective recognition cavities complementary to the VAN template molecule in the final MIPs@GQDs@DA probe.When we used excitation light with a wavelength of 360 nm to excite the composite material, MIPs@GQDs@DA emits a stable fluorescence peak at 460 nm. Vancomycin can sensitively and rapidly bind to MIPs@GQDs@DA, thereby quenching the fluorescence generated at 460 nm. Calculations revealed that the quenched fluorescence intensity at 460 nm exhibits a good linear relationship with the concentration of vancomycin, within a linear range of 0–80 μg/mL, and a detection limit of 0.83 μg/mL (S/N = 3). This probe was applied to detect vancomycin in real human serum samples, and the experimental results were consistent with the expected outcomes.