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.

Quantification of neomycin in rubella vaccine by off/on metal ion mediated photoluminescence from functionalized graphene quantum dots.

The determination of neomycin sulfate was made using photoluminescent amino-functionalized graphene quantum dots (obtained from hydro-exfoliation of a mixture of citric acid and glutathione). From the several ions tested, Fe was the best mediator to enable an off/on photoluminescence effect used for quantification. The mediation of Fe was found to be crucial as it is responsible for the photoluminescence quenching effect, due to the interaction with quantum dots surface, also having large affinity towards neomycin that removes Fe from the surface of GQDs, consequently, promoting restoration of the original nanomaterial photoluminescence.