▎ 摘　　要

An electrochemical aptasensor modified with thionine (TH), graphene-polyaniline composite film (Gr-PANI), and gold nanoparticles (GNPs) was fabricated for convenient and sensitive determination of kanamycin. Gr-PANI nanocomposite can enhance electron transfer between work electrode surface and potassium ferricyanide. TH has excellent electrocatalytic activity toward the redox of small molecular compounds. GNPs acted as the transducer between the aptamer and Gr-PANI composites. Based on the above-mentioned advantage of these three nanaomatrials, we took advantage of their synergistic effects to fabricate a simple and sensitive aptasensor for kanamycin detection in real milk samples. The aptasensor was characterized by cyclic voltammetry, scanning electron microscope, and electrochemical differential pulse voltammetry. The experimental conditions such as concentration of aptamer, incubation temperature, time, and pH were optimized. Based on the above optimum conditions, this aptasensor showed a favorable analytical performance for kanamycin detection with a detection limit of 8.6 x 10(-9) M.