A colorimetric/SERS dual-mode sensor based on ferric ion-dopamine@Au–Ag-Au Janus NPs for acrylamide determination in baked goods

This study successfully developed a colorimetric/SERS dual-mode sensor for determining acrylamide in baked goods based on the excellent peroxidase-like activity and Raman activity of Fe-PHS@Au–Ag-Au Janus NPs. In colorimetric mode, the thiol-ene Michael addition between acrylamide (AA) and glutathione (GSH) efficiently eliminates GSH-induced peroxidase-like activity inhibition. The peroxidase-like activity of Fe-PHS@Au–Ag-Au Janus NPs gradually recovered, and the blue color of the solution gradually deepened with the increase in AA dosage. In surface-enhanced Raman spectroscopy (SERS), Apt-Fe-PHS@Au–Ag-Au Janus NPs can selectively capture AA and bind specifically, leading to the dissociation of Apt and Fe-PHS@Au–Ag-Au Janus NPs. The Raman activity of Apt-Fe-PHS@Au–Ag-Au Janus NPs decreases due to the dissociation of Apt. The dual-mode sensor was utilized for the determination of acrylamide in the concentrations range from 0.05 to 20 µg·L −1 with detection limits of 0.06 µg·L −1 (SERS) and 0.01 µg·L −1 (colorimetric). The recovery in baked samples was between 91.0 and 108.0%. Graphical