A fluorescent aptasensor was developed and applied to detect aflatoxin B1 based on Au@Fe3 O4/aptamers/aminofunctioned carbon quantum dots magnetic nanocomposites which were constructed self-assembly.The selective interactions between aflatoxin B1 and the aptamer in the samples cause release of the aminofunctioned carbon quantum dots which remains in the solution after magnetic separation.A linear fluorescence signal response to aflatoxin B1 concentration is obtained over a wide aflatoxin B1 concentration ra...