A novel CdSe/CdS quantum dot-based competitive fluoroimmunoassay for the detection of clenbuterol residue in pig urine using magnetic core/shell Fe3O4/Au nanoparticles as a solid carrier.

Quantum dots (QDs) are semiconductor fluorescent nanoparticles, which can be used for food safety or environmental monitoring with high sensitivity. This work demonstrates the feasibility of detecting clenuterol residue in pig urine using CdSe/CdS quantum dots as fluorescent labels based magnetic core/shell Fe3O4/Au nanoparticles (MCFN) as solid carriers. The detection of clenbuterol is carried out by a fluoroimmunoassay-based biosensor using competitive binding between conjugated clenbuterol antigen-CdSe/CdS QDs and free clenbuterol with immobilized clenbuterol antibodies on MCFN. This assay method allows for clenbuterol determination in a linear working range of 0.5-20000 pg mL(-1). It would provide a simple, rapid, and ultra-sensitive detection method for clenbuterol or other biomolecular analysis.