N-doped graphene quantum dots combined with Ag nanoparticles for luminescence based analytical sensing of gentamycin after solid-phase extraction in a molecularly-imprinted polymer.

A luminescence-based method was developed to detect gentamicin using silver nanoparticles (AgNPs) associated with nitrogen-doped graphene quantum dots (N-GQDs). When gentamicin sulfate interacts with the AgNPs/N-GQDs system, the characteristic blue fluorescence of N-GQDs, which had been previously turned off by AgNPs, is restored. Under specific conditions (such as the amount of synthesis dispersion and pH), this AgNPs/N-GQDs probe enabled quantification of gentamicin ranging from 3.0 × 10 to 6.0 × 10 mol L. To address interference from other substances during the analysis, a solid-phase extraction, with a kanamycin-imprinted polymer cartridge, enabled accurate results. Two veterinary pharmaceutical samples were used to test the method and results were in agreement with those achieved by obtained using high-performance liquid chromatography with analyte chemical derivatization. This new method is straightforward, sensitive, and selective, and it is also considered eco-friendly (0.63 score Analytical greenness calculator) since it avoids the use of toxic chemical derivatization reagents, use nanoquantities of carbon and silver based nanomaterials and aqueous systems.