Abstract: In this study, a highly sensitive portable platform with colorimetric and fluorescent dual-mode signal output for the detection of aflatoxin B1 (AFB1) was developed based on the reaction between glutathione and a composite nanomaterial consisting of manganese dioxide (MnO2) nanoparticles and graphene quantum dots (GQDs) as a substrate. The recognition probe was prepared by using silica nanoparticles as a carrier to enrich glutathione and AFB1 aptamers. Under optimal conditions, analytical figures of merit such as specificity of this method were studied. The regression equation for colorimetric signal was ΔA = − 0.275 − 0.021lgC and the detection limit was 2.732 × 10-12 g/mL; the regression equation for fluorescence signal was ΔF = 928.733 + 71.779lgC and the detection limit was 1.667 × 10-12 g/mL. Both methods had good detection specificity. The proposed method was applied in the detection of food samples, such as milk, rice, oatmeal, soy sauce and white vinegar with higher accuracy, compared with the traditional method.

Key words: aflatoxin B1; manganese dioxide nanoparticles; graphene quantum dots; aptamer; dual-mode signal