A competitive-type electrochemical immunosensor based on Ce-MOF@Au and MB-Au@Pt core-shell for nitrofuran metabolites residues detection.

Abstract A novel competitive-type electrochemical immunosensor based on square wave voltammetry (SWV) response was developed for the quantitative detection of 1-Aminohydantoin (AHD). To improve the conductivity of this immunosensor nanocomposites with good electrical conductivity were prepared as a signal amplification platform for the immunosensor by growing Au nanoparticles on the surface of Ce-based metal–organic framework (Ce-MOF). In addition, methylene blue (MB)-loaded Au@Pt and coating antigen (OVA-AHD) connected as a signal label. When the target was introduced, it competed with the coating antigen for the Ab, which led to a reduction in the number of signal probes bound to the Ab. The concentration of AHD can be determined by SWV detection of the MB signal loaded on the signal labels. Under optimal conditions, the wide linear range of 0.001–1000 μg /L and a low detection limit of 1.35 × 10-7 μg/L were achieved. Ultimately, the developed method displayed excellent specificity in practical applications, providing a promising probability to detect nitrofuran metabolites residues to guarantee food safety.