High-performance colorimetric immunoassay for determination of chloramphenicol using metal-organic framework-based...

Metal-organic frameworks (MOFs) as carriers for high-capacity loading of HRP-IgG and gold nanoparticles are introduced, to prepare MOF hybrids with enhanced peroxidase activity. The prepared MOF hybrids were employed to establish an indirect competitive colorimetric immunoassay for chloramphenicol (CAP) detection, in which the limit of detection for CAP is 0.006 μg·L^-1, only one-fifth of that of the conventional ELISA using the same antibodies and antigens. The linear range was 0.008-0.108 μg·L^-1, and the recovery of spiked milk samples varied in the range 76.0-106.0% through three independent experiments. Our proposed colorimetric immunoassay using the MOF hybrid immunoprobe provides a novel platform for ultra-sensitive determination of CAP residues, and it also could be used as a signal amplification model for the high-performance colorimetric immunoassay in food safety monitoring.