Antibody-functionalized reduced graphene oxide films for highly selective capture and purification of aflatoxins

Pyrenylbutyric acid and streptavidin were coupled to films of reduced graphene oxide (rGO) and then conjugated to a biotinylated broad-spectrum monoclonal antibody against aflatoxins (AFs). It is shown that such films can efficiently and selectively capture AFs inculding AFB₁, AFB₂, AFG₁, AFG₂, AFM₁ and AFM₂. The rGO films were characterized by using scanning electron microscopy, energy-dispersive spectroscopy, and raman spectroscopy. The selectivity and purification performance of the antibody-loaded rGO films were investigated. They were applied to the purification of extremely small samples (100 μL) of AFs-spiked rabbit serum after enzymatic hydrolysis. The AFs were analyzed by ultra-performance liquid chromatography coupled to tandem mass spectrometry. The limits of detection for the six AFs investigated ranged from 50 to 170 pg·mL^-1. The average recoveries of AFs in spiked rabbit serum samples ranged from 55% to 75%, with relative standard deviations of less than 9.4%. Graphical abstract Design of a multifunctional sandwich film that consists of a reduced graphene oxide film base, a pyrenylbutyric acid middle layer and a broad-specificity anti-AF monoclonal antibody surface layer. It was successfully applied to the determination of aflatoxins in only 100 μL of rabbit serum samples with satisfactory selectivity and acceptable accuracy.