A magnetic sensing probe of zinc oxide decorated carbon foam and nitrogen-doped graphene quantum dots in a selective polymer for the determination of florfenicol in milk

An optosensor based on fluorescence quenching was developed and utilized for the determination of florfenicol. The probe comprised nitrogen-doped graphene quantum dots (N-GQDs), zinc oxide decorated carbon foam (ZnO*CF) and magnetite nanoparticles (Fe3O4) in a molecularly imprinted polymer (MIP). The fluorescence intensity of the N-GQDs/ZnO*CF/Fe3O4/MIP probe was emitted at 410 nm. The intensity of fluorescence emissions decreased linearly with increments of florfenicol from 0.50 to 100 & mu;g L-1. The limit of detection was 0.17 & mu;g L-1. The developed optosensor based on the nanocomposite probe was applied to determine florfenicol in milk samples. Recoveries from 90.5 % to 101.5 % were achieved with a relative standard deviation (RSD) lower than 3 %. The real-sample analysis results of the proposed method agreed well with the results of HPLC analysis. The developed optosensor showed good sensitivity and selectivity and could be applied for the determination of other substances in various samples by adjusting some measurement conditions.