Chemiluminescence immunoassay using magnetic nanoparticles with targeted inhibition for the determination of ochratoxin A.

In this work, a chemiluminescence (CL) immunoassay with targeted inhibition was developed for the determination of toxins in food products. For sample treatment, amine-functionalized magnetic nanoparticles (MNPs) were synthesized to extract target molecules, and horseradish peroxidase (HRP) tagged on an antibody was used as a label for CL reaction. In particular, amine-targeted inhibition using aldehyde, i.e., specifically capping the amine with an alkyl group, was developed for a non-specific extraction platform to lower background and improve signal-to-background ratio. For demonstration, ochratoxin A (OTA) was determined in rice using a lab-built drop-type chemiluminescence (DCL) system with luminol-H2O2 reagent. The obtained limit of detection was 1.39 pg mL(-1), which was about 7.3 times better than that of ELISA. Recovery of the method in the range of 87-99% was observed, which was compared with ELISA.